I am thinking of replacing my factory HU with a Pioneer Premier 480MP. At least I think thats the model #. Its the only one on Crutchfields website n the price range of the one I looked at at a local sound shop, and it has the 3 pre-amp outputs too. Anyway...any info on this particular unit..how good is it, what kind of sound can i expect, since it has the 3 pre-amp RCA's ...doesnt that mean I can ad amps for the front, the back and for a sub? and finally...should I pay the extra money (I think they said $30) for the shop to install it, so I get the 2 year warranty instead of a 1 year one? please reply