GT3
The Spire GT3, manufactured by British specialist constructor Spire Sports Cars as purpose-built sports racing prototype for domestic motorsport championships, features motorcycle-derived powertrain utilizing Honda CBR1000RR Fireblade or Suzuki GSX-R 1000 K8 four-cylinder engines producing approximately 170-180 horsepower at rear wheels from 1,000cc displacement revving to 13,000 rpm, paired with sequential six-speed transmission driving rear wheels through extreme lightweight tubular steel space-frame chassis construction achieving just 490 kg wet weight or 580 kg including driver. Extraordinary power-to-weight ratio exceeding 310 horsepower per ton enables devastating acceleration achieving lap times comparable to British Touring Car Championship machinery despite modest absolute power output, supported by inherent aerodynamic downforce from purpose-designed bodywork constructed from fiberglass and carbon fiber composite materials.
The Spire GT3 represents accessible entry to serious sports prototype racing competing in British championships including RGB (Rear-engined, Green, Budget racing), Sport 1000, and Bikesports series emphasizing cost-controlled competition through control tire regulations mandating Avon ZZS A048 rubber and prohibition of wings or additional aerodynamic devices maintaining competitive parity. Advanced engineering features fully adjustable suspension geometry, competition-spec dampers, ventilated disc brakes with multi-piston calipers managing deceleration from high speeds, and characteristic motorcycle engine power delivery creating engaging driving experience requiring precision throttle control and gear selection strategy. Popular among club racing enthusiasts seeking professional-level performance at fraction of GT3 homologated machinery costs, the Spire GT3 delivers genuine circuit capability achieving sub-50 second lap times at Brands Hatch Indy configuration, minimal maintenance requirements benefiting from proven motorcycle engine reliability and extensive aftermarket parts availability, and comprehensive constructor support through Spire Owners Club establishing strong community around British sports prototype racing tradition representing grassroots motorsport accessibility combining professional performance with enthusiast-friendly ownership costs.