Is it possible to replace the stock amp while keeping the stock bluetooth and headunit? If so, what would have to be done to keep the stock bluetooth working?
Another question I had was which speakers you guys prefer for the 4 ohm rear coaxial speakers that would go along well with DLS UP6 fronts.

I have a 2007 Premium Coupe (no Navi), Thanks.

 

The Bluetooth goes to the BOSE headunit, before the signal goes to the Amp.

I'll avoid speaker questions, buy the best you can afford, I still have my stock speakers and BOSE Amp with an aftermarket head unit, and I'm happy.