Every car is same. Just different bodyshell and effects via physics. About suggestion above, there is explanation about why there is not given "normal" tires.
I think I side with FreeScirocco's thoughts of it. After several threads and pages across the internet, I think it is nothing but just stupid show-off, just like burnout.
But I admit it, despite being stupid, it looks damn cool!
EDIT: HOWEVER, it does not mean it is BADLY tuned engine. In this thread there are many things left which have not given thought about it: Fuel, Timing, Type, Material and other indirect aspects. But it is not perfect either due simply limitations. Or even rules regulations in motorsport.
EDI2: But why backfire occurs on tuned engines? There is various thoughts of it, but I think it has to do about because calculations about power/loss ratio, overshooting with offset tuned engine for better result, rather than having less power = less power loss. This is because competition in terms of motorsport.
Still, my thought isn't on perfect scale and won't bother to go more detailed shot for it, but I stick with FreeScirocco's thoughts. ( Well... facts ) With assist of Gutholz's as well.
About Season 2, Round 1 will not start in this week and is unsure in when exactly it starts. Reason is very simple: being busy and critical fixes aren't that easy to do.
There is a flaw about getting spectated by idle, counter might start after pitstop and won't go off till it is zero and force spectates. There is fix coming in somepoint, once everyone has time.
Sorry about this, but stay tuned! Please patience!
EDIT: Seems like the flaw is much more critical, so indeed it will get postponed