Hey guys...

For my 03 M3, I'm planning to install a sound system. I'm not sure if I'm just going to go for something that's just good to listen to... or go all out for competition.

Since I don't have a regular size (I or E) deck and have nav, I don't want to change the head unit or anything. How would you guys wire that? The only thing I can think of is getting high inouts and go through a high-low converter... but that sounds like crap. Any way around this??