So as some of you may know, I'm not exactly mechanically inclined. I've been on these forums for a long time, but I still don't understand a lot about the different mods people put on their cars. Downpipes, headers, air intakes, I've read the safely modding your car thread which explains a bit about different mods, but from what I've read it doesn't seem to explain exactly what it is they do. For example I know what an air intake looks like, and my guess would be it helps cool the engine by filtering extra air and cooling it. But again that's just my guess.
Is there any decent resource for learning about common mods and what they do, and the expected result?
Thanks.