Sorry, I know you guys get a butt load of these questions, but I read that on an amp install for an xB you should not tap the rear outputs from the deck, because they have a seperate amplifier. Is this true? I don't want to sap the signal strength for an line out converter from the front speakers, since that output already drives the tweeters too. . . is there actually a seperate amplifier(sounds weird) and is the xA like this too?

and do you guys think a small 250watt Kenwood amp will fit in the storage area underneath and not overheat?

You will be fine tapping off the head unit, a easier way to do it is to just tap off the back speakers t-tap in the wires. I did this because I knew it was temporary until I got a new head unit.

As far as your amp goes you should be fine I was running a 1000watt Hollywood Sound Amp in the storage area. I always ran it hard it only shut off on me once on the way to vinyl mayhem (about a three hour round trip).

I tapped into the front speaker outputs on the back of the head unit, and it works fine. Im running a 400w mono amp under the passenger seat.