Looking to replace my rear speakers. Looking at getting away from bose, little by little, due monetary constraints. ATM would like to start with replacing bose amp and the 2 6x9s. Will not be adding a sub, need the trunk space for my surfboard and scuba gear, so I'll be using the same setup as bose system, i.e. using the 6x9 for low frequencies. Not really sure how many channels I need for the amp, any help there would be great. Ideally, I would like to mount the amp where the bose amp is located and to keep the price of these components under $1k. Any advice would be appreciated.

To clarify, I guess I'm more interested in what specs to get. Because I want to keep the front speakers which are at 2 ohms, would that mean I'm stuck with an aftermarket amp at 2 ohms? And do I need 6 channel amp to run everything if I just wanted to stick with 1 amp to save room.