si os fijais en el link de Randy:
http://vauxhall.co.uk/vx/vxr/onthetr.../carsengine.do

Standard Engine: Z20NET 2.0-litre Turbo 16-valve Racing Engine: Sodemo 4-cylinder in-line
16 valves
Dual overhead camshafts
Transverse installation
Restricted air intake (TOCA component)
Naturally aspirated (TOCA restriction)
se sustituye el sobrealimentado z20net 2.0 litos turbo de serie, por un 2.0 16v atmosferico con brida, para adaptarse al reglamento.

Maximum Power: Approx. 300 bhp at 8500 rpm Maximum Torque: Approx. 260 Nm at 7000 rpm