Car Audio Advice

[Keyser Soze]

I'm looking to upgrade the audio system in my 2003 Nissan 350Z. I bought the model that did not come with the Bose audio system and i'm trying to decide if I should go to Nissan and just upgrade it to the Bose or go get a custom system built.

I'm looking to spend around $700-800 for the system, maybe more if I decide to add a nav/dvd system.

Any people around here up on car audio that can help me out?

I need to be able to hook my MiniDisc player to the system as well, I believe thats through an FM transmitter.