No 1c does equal 1bhp! I work with rolling roads a lot in my job and monitor temp's of all sorts of cars, petrol, diesel, turbo, supercharged, N/A. It matters a huge amount on boosted engines as the temps are so much hotter it's more important to bring them down to ambient. If you start with a hotter inlet temp it's harder to bring it down to ambient so will be worse entering the throtle than it would be if you had a cooler inlet temp to start with.
Often find as well aftermarket IC's aren't as good as OEM IC's even if they are bigger in size (a lot of OEM IC's have V.good cores as they are usually limited for space so make the most of it!).
Monte Carlo Blue M3 Comp