This game makes no sense.
1. A one point change drops your power obnoxiously low.
2. No matter what the part, if you install it and then uninstall it, the power doess not drop/increase as you would think. Now, granted that there is the matter of engine wear, but one assumes the horsepower is projected. So you install the Borla exhaust and gain 270 over your original 266 hp. But if you uninstall it you drop to 235 hp. Put it back on and gain 280 hp?
I know almost nothing about engines, but I do know that, from playing with one of those engine design programs, that rocker ratio and other things matter. Are players supposed to spend all day hunting for formulas and programs, such as race pro, to find out where their cars' power will go after an upgrade. Should they search the websites of the manufacturers of these parts? What's the ID number of the part the program uses?
Do all the manufacturers have websites? If they do, will they have the needed data or charge you for a catalog, or just make you wait on an e-mail response? Will you be spammed by Lunati?
The guys behind this got a head of themselves in my opinion. To any lay observer the engine physics do not make sense.
I may be completely wrong, but I don't think I am.