Relocating the computer
 

Someone suggested me to relocate the FI computer on the other side of the firewall behind the passenger seat because it is cooler there ( in theory ). Does it make sense?

Yes it is cooler, but I don't really see the point. The brain is fairly sealed. It would just mean another hole for you to make and a bracket for you to fabricate. I don't think the brain gets anywhere near as hot as the engine and it seems to be doing just fine where it is on my car.