I'm just doing the trunk for now. Hopefully that'll keep me happy, spending money on a car that I barely drive is pretty dumb. I don't mind the stock components anyway, they're liveable. Here's what's going in:
Alpine MRP-M350 (456W bench tested RMS)
Alpine SWR-1041D (10" Type-R)
Custom 0.77ft^3 sealed box
Should be enough for a solid thump. I would have started with the headunit (where you should always start) but the E46's dash just doesn't look right with an aftermarket deck.
I'm an Alpine whore now. Great products in general man.