Porsche 981 Cayman GT4 / BMW E46 M3
The Porsche 981 Cayman GT4 makes 385 horsepower and costs $94,000. The BMW E46 M3 makes 337 horsepower and costs $40,000—a $54,000 price gap (135% more expensive for the GT4) for 48hp more power. Across 85 shared tracks with 25 unique comparison scenarios, the GT4 wins by 1.48 seconds overall, and when you filter the comparison data on this page for matched modifications and matched tire treadwear, the GT4 wins 56.1% of battles with a 1.83-second average gap.
This is Porsche's first-generation Cayman GT4 (2016-2018) versus BMW's E46 M3 (2001-2006). The 981 weighs 3,050 lbs. The E46 weighs 3,241 lbs—191 pounds heavier. The 981 has 48hp more power (385hp vs 337hp), yet wins only 56.1% of matched battles—the closest fight in the GT4's comparison history. The E46 wins 43.9% of the time when everything is equal.
The 48-Horsepower Gap: 981 Flat-Six vs E46 S54 I6
The E46 M3's S54 3.2L straight-six makes 337hp at 7,900 rpm and 262 lb-ft at 4,900 rpm. Power-to-weight: 9.62 lbs/hp. The 981 GT4's 3.8L flat-six makes 385hp at 7,400 rpm and 310 lb-ft at 4,750-6,000 rpm. Power-to-weight: 7.92 lbs/hp—an 18% advantage.
The 981's mid-engine layout creates telepathic handling, but the E46's front-engine 51/49 weight distribution and S54 engine (105 hp/liter specific output) deliver a driving experience purists still consider BMW's peak. The 981 has more power (48hp) and more torque (48 lb-ft), yet the E46 competes nearly evenly—winning 43.9% of matched battles.
What the Filtered Data Reveals
- Matched mod + matched tire (66 laps): 981 wins 56.1%, E46 wins 43.9%, 1.83s gap. This is the smallest advantage any GT4 has shown in matched scenarios across all comparisons. The E46's 191-pound weight disadvantage is minimal, and the S54's character keeps the fight competitive despite the 48hp deficit.
- 981 advantage grows with modification levels: When both run race-prep, the 981's chassis handles more power more effectively. A 450hp 981 (headers, exhaust, tune) pulls away from a 400hp E46 (supercharger) because the mid-engine platform distributes power better.
- E46 wins scenarios when running higher modifications: A heavily-modified E46 with supercharger (450-500hp for $12,000-15,000) can challenge or beat a lightly-modified 981. The comparison data shows the E46's modification ceiling transforms the fight entirely.
The $54,000 Price Gap and Modification Potential
E46 M3: $40,000 buys the S54 straight-six (BMW's last naturally aspirated masterpiece before the E92), 337hp, and 10-15% annual appreciation as values climb from $25,000 in 2019 to $45,000+ in 2025. The S54's naturally aspirated ceiling is limited: headers ($2,500), exhaust ($2,000), tune ($1,500) = 365-380hp. To compete with the 981's 385hp requires supercharging ($10,000-12,000) for 450-500hp.
981 GT4: $94,000 buys mid-engine perfection, 385hp, GT3-derived suspension, and the first Cayman GT4 (appreciating 5-8% annually). The flat-six's modification ceiling reaches 450hp with exhaust ($4,000) + tune ($2,000), plus the chassis handles 500hp+ with supporting mods ($8,000-12,000 total).
That $54,000 premium buys 48hp more power out of the box, mid-engine handling, and a higher modification ceiling—but the E46's 43.9% win rate when matched proves the price gap doesn't guarantee domination.
The Verdict
Choose the BMW E46 M3 if you want the S54 straight-six experience at $40,000, accept losing 56.1% of matched battles (but winning 43.9%!), and value the E46's analog character. This is the closest any car comes to competing with a GT4 when everything is equal—the E46 wins nearly half the time for 43% of the price.
Choose the Porsche 981 Cayman GT4 if you want mid-engine physics at $94,000 and prioritize winning more than losing. You're paying $54,000 more (135% premium) for a 56.1% win rate and 1.83-second advantage when matched. The 981 is the choice for drivers who want Porsche's track-weapon pedigree, but the E46's 43.9% win rate proves this is the most competitive GT4 battle in the database.
LapMeta's 1.48-second overall gap and 1.83-second matched-condition gap show the 981's superiority is real but narrow. The E46's 191-pound weight disadvantage and 48hp power deficit translate to losing 56% of the time—but winning 44% of the time proves the S54's character and E46's chassis are legitimate. For the driver who wants the best M3 under $45,000, the E46 competes nearly evenly. For the driver who wants the mid-engine advantage, the 981's 56% win rate proves that $54,000 buys measurable—but not overwhelming—superiority.