BMW E46 M3 / Porsche 718 Cayman GT4

The BMW E46 M3 weighs 3,241 pounds. The Porsche 718 Cayman GT4 weighs 3,247 pounds—a 6-pound difference that's effectively identical. Yet across 88 shared tracks with 106 unique comparison scenarios in LapMeta's database, these cars are separated by 3.73 seconds, and when you filter the comparison data on this page for matched modifications and matched tire treadwear, the GT4 wins 86.3% of battles with a 6.66-second average gap.

This isn't a close fight. This is a 17-year technology gap showing what happens when you compare a 2000-era front-engine sports sedan to a 2019-era mid-engine track weapon. The E46 M3 costs $40,000. The GT4 costs $125,000—an $85,000 price premium (213% more expensive) that buys 77hp more power, mid-engine physics, and two decades of chassis evolution.

The 77-Horsepower Gap and Mid-Engine Physics

The E46 M3's S54 inline-six makes 337hp at 7,900 rpm and 269 lb-ft at 4,900 rpm from 3.2 liters. Power-to-weight: 9.62 lbs/hp. The 718 GT4's 4.0L flat-six makes 414hp at 7,600 rpm and 310 lb-ft at 5,000-6,800 rpm. Power-to-weight: 7.84 lbs/hp—a 19% advantage.

But the power gap only tells part of the story. The GT4's mid-engine layout places that 414hp directly behind the driver, creating near-perfect weight distribution and a low polar moment of inertia. The E46's inline-six sits ahead of the front axle, creating understeer at the limit and requiring more driver input to rotate the chassis.

Mid-engine physics beats front-engine engineering every time when weight is identical. The GT4 turns in with telepathic precision; the E46 requires persuasion. The GT4 settles instantly on throttle lift; the E46 needs brake and weight transfer. The comparison data proves this: even when modifications and tires match, the GT4 wins 86.3% of battles.

What the Filtered Data on This Page Reveals

The comparison tables break down performance by modification level and tire treadwear, showing a consistent pattern:

• Matched mod + matched tire (95 laps): GT4 wins 86.3%, M3 wins 13.7%, 6.66s average gap. Relative speeds at -0.15 (M3) and -0.41 (GT4) show both cars running faster than predicted, with the GT4 driver extracting slightly more performance.
• Medium/medium, TW200/100 (78 laps): GT4 wins 94.9% with 6.94s gap. The GT4 on stickier slicks (TW100) versus the M3 on street tires (TW200) creates a grip advantage that amplifies the power and chassis differences.
• Medium/medium, TW100/100 (25 laps): GT4 wins 80.0% with 5.38s gap. Even with matched slicks, the GT4's mid-engine layout and modern aerodynamics dominate.
• Race M3 vs light GT4, TW40/200 (97 laps): M3 wins 67.0% with 4.64s gap. This is the only scenario where the M3 consistently wins—when running race-level modifications (likely 400hp+) against a lightly-modified GT4 on street tires. The S54's naturally aspirated ceiling reaches 380-420hp with headers, cams, and aggressive tuning.

Use the comparison filters on this page to see the pattern: the GT4 wins unless the M3 is heavily modified AND the GT4 is stock. Even a one-level modification advantage for the M3 only closes the gap—it doesn't reverse it.

The $85,000 Price Gap: What You're Buying

E46 M3: $40,000 purchase price for a 20+ year-old icon with legendary S54 engine character, but also with $8,000-15,000 in deferred maintenance likely needed (rod bearings, VANOS, subframe reinforcement, cooling system).

718 GT4: $125,000 purchase price for a modern track weapon with mid-engine balance, GT3-derived suspension, and Porsche's legendary build quality—but also $3,000 annual maintenance costs and parts at Porsche pricing.

That $85,000 difference buys:

• 77hp more power (414hp vs 337hp)
• Mid-engine physics instead of front-engine compromise
• 17 years of chassis evolution (adaptive dampers, modern aero, improved geometry)
• No rod bearing time bomb, no VANOS failure risk, no subframe cracking concerns
• Factory warranty and modern reliability versus 20-year-old German engineering at end-of-life

Is that worth $85,000? The data says: if you want to win 86.3% of track battles when everything is equal, yes. If you want the most engaging car per dollar, no.

The E46 M3's "Big 3" Maintenance Reality

Every E46 M3 buyer in 2025 faces "The Big 3" maintenance issues:

1. Rod bearings ($2,500-4,000): The S54's rod bearings fail unpredictably between 80,000-120,000 miles, causing catastrophic engine damage if not replaced preventatively. This isn't an "if"—it's a "when." Budget for replacement immediately if service history doesn't show recent replacement.

2. VANOS ($1,500-2,500): The variable valve timing system's tabs break off and end up in the timing chain, causing power loss, rough idle, and potential engine damage. Symptoms include hesitation, cold start issues, and check engine lights.

3. Subframe reinforcement ($1,000-2,000): Even babied E46 M3s suffer subframe cracks where the rear suspension mounts to the chassis. If left unaddressed, sections of the rear floor can rip away. This requires welded reinforcement plates—a permanent fix but labor-intensive.

Total deferred maintenance for a "cheap" $40,000 E46 M3: $5,000-8,500 minimum. Add cooling system refresh ($1,500) and you're at $6,500-10,000. The real entry cost is $46,500-50,000 to own a properly sorted example.

The GT4 at $125,000 has none of these issues. You're buying modern reliability where oil changes and brake jobs are the only concerns.

Wheelbase and Handling Character

The E46 M3's 2,730mm wheelbase is 246mm (9.7 inches) longer than the GT4's 2,484mm. This creates opposite handling philosophies:

The E46's longer wheelbase provides stability at speed but requires more distance to rotate through corners. The front-engine layout creates understeer at the limit—characteristic BMW behavior that requires trail-braking to rotate the rear. Experienced drivers extract lap time through technique; intermediates push and hope.

The GT4's compact wheelbase and mid-engine layout rotate instantly on throttle lift. Turn-in is telepathic. The car settles mid-corner with minimal steering input. Exit traction is superior because weight shifts onto the rear-mounted engine under acceleration. The chassis flatters intermediate drivers and rewards experts.

The comparison data's relative speeds show this: GT4 drivers consistently post negative relative speeds (faster than predicted), while M3 drivers show wider variance. The GT4's inherent balance makes it easier to drive consistently fast.

Naturally Aspirated Character: S54 vs 4.0L Flat-Six

Both engines are naturally aspirated masterpieces, but from different eras:

The S54 redlines at 8,000 rpm with individual throttle bodies feeding each cylinder. Peak power at 7,900 rpm requires keeping the engine singing. Mid-range torque plateaus at 4,900-6,500 rpm, creating a linear pull that rewards high-RPM driving. The inline-six sounds glorious—a mechanical wail that defines early-2000s BMW M Division.

The GT4's 4.0L flat-six pulls from 5,000 rpm to 8,000 rpm redline with 310 lb-ft available across a 3,800-rpm range (5,000-6,800 rpm). Power delivery is broader, more accessible, and equally satisfying. The flat-six howl—borrowed from the GT3—is one of the finest engine notes in modern production cars.

Both require commitment to high-RPM driving. Neither delivers turbo torque at low RPM. The difference: the GT4's extra 77hp and mid-engine traction mean you use that power more effectively on corner exit.

The Verdict

Choose the Porsche 718 Cayman GT4 if you want the fastest, most capable track car and have $125,000 to spend. You're paying $85,000 more than the E46 M3 for an 86.3% win rate when everything is equal, mid-engine physics that can't be replicated through tuning, and modern reliability without rod bearing time bombs or subframe concerns. The GT4 is the choice for drivers who demand peak performance and can afford Porsche's pricing.

Choose the BMW E46 M3 if you value the S54 engine's character, accept $6,500-10,000 in deferred maintenance as entry cost, and understand you're buying a 20-year-old icon that loses 86.3% of matched battles to a purpose-built track weapon costing 3x more. At $46,500-50,000 true cost (purchase + Big 3 maintenance), the E46 delivers engaging driving and legendary engine character—just not GT4-level lap times.

Use the comparison filters on this page to see the pattern: the GT4 dominates unless the M3 is race-prepped. The only scenario where the M3 wins is running race-level mods (400hp+) against a lightly-modified GT4 on street tires. That's not a fair fight—it's proof that even with a $10,000 race build, the E46 only ties the GT4 when the Porsche is handicapped.

LapMeta's 3.73-second overall gap and 6.66-second matched-condition gap show the GT4's overwhelming superiority. The $85,000 price premium buys 86.3% win rate, mid-engine perfection, and 17 years of technological evolution. For most track day drivers, the E46 M3's value proposition is nostalgia and S54 character—not lap times. For those who prioritize winning, the GT4's 86.3% win rate proves that modern engineering and mid-engine physics can't be overcome by tuning a 20-year-old front-engine sedan.

The E46 M3 is an icon. The 718 GT4 is a weapon. Choose based on whether you value history or victory.