Hey all, was thinkin of upgrading my whole audio setup on my 2000 es300. Heres the rundown I was thinking of.

Infinity speakers all around(tweets, doors, and 8" in rear)
Pioneer Avic-z1(navi, hdd, touchscreen, the whole 9 yards)
and possibly another 8-10" sub in the rear. Any other suggestions or does this list sound ok?

Another question. If I replaced the stock 8" sub, would I have to get an amp to power it, or does it have a stock amplified hidden somewhere that I could hook it up to?