In my opinion, dont limit the maximum displacement to 2200cc. Make it open to any displacement, as long as the interior and exterior still on the road conditions. I think this would attract more participants from other carmaker other than proton-mitsu. For example Skyline,Supra,M3,etc. Maybe some people might question the larger displacement as an advantage to those skyline,supra owners, but we must take into consideration their weight as well. Even nowadays, there are many on the road wira/satria evo powered not running 2.0 litre anymore, some even running 2.4 litre! with GT40 / GT42 / S374 /S480..

So, overall everyone has their own advantage. You get some, you lose some..Only then we can see Satria evo smack skyline's 6 potter down.. like the Batu 3 and pasir gudang old days..hahaha...
Just my worth..