DV, nope I'm not holding any info back honest
I'm just an armchair mechanic, I write video games (racing games mostly), writing various simulations has given me a pretty good understanding of at the least the basics of most aspects of car design. And generally when I come accross something I don't understand I find someone to ask.
The back pressure question annoyed me for the longest time aswell, I couldn't see how it could be productive, but one of the local tuners gave me the explanation above.
I certainly wouldn't consider myself any sort of expert when it comes to this stuff.
Recently I decided it would be very cool to actually build a real car (it's something I've wanted to do since I was a kid) rather than just simulating one, still haven't decided what I want to or even can build yet.