Ughh confused

If you are removing the factory amp, then you will need to replace your head unit, which will render your steering wheel controls useless. I'm not sure that driving your factory speakers with an aftermarket head unit is ok. Their may be an impedance mismatch, or you could otherwise damage the speakers. I would recommend replacing them also. By the way, why exactly are you removing your factory amp to begin with?

all right... with an aftermarket headunit you can run the speakers from the headunit itself or a seperate amp, but the problem is that the factory amp does not push out much power, so you will be make sure to set the gain right on the new amp/headunit so you dont overpower them..... and you can keep you steering wheel controls, you just need to buy an adapter, do a search people have asked about it before.......... ALSO you will not be able to use the factory amp with the aftermarket headunit because it uses a differant input than any headunit i know of has.