Who Has Replaced The Factory Amp In A Gs?

[maneesh]

preparing for my carputer install, and I will be taking out the factory headunit. apparently, the factory amp will not work without the factory headunit, sooo..any ideas on what amp I can use as a replacement?

At the moment, I have tweeters and door speakers up front, speakers in each rear door, and a factory sub.

Do I use a 5 channel amp? Are they all the same size? Ideally, I want to be able to put the new amp in the same place as the factory one (it's behind the glovebox).

Forgive my ignorance, it's been many moons since I played around with car audio. I just want to get something reasonably priced that will work with my factory speaker setup.

Thanks!