I just bought a used 2004 GMC Envoy XUV and i want to upgrade my system. My budget is pretty good like 1500-200 and i went around today and i was looking at headunits between the pioneer dehp20mp and the alpine(about 400$)...for speakers i was looking at diamonds and MB Quartz....but my big problem is that there is no room anywhere in my car to put an AMP and the guy at the audio store said that the Diamonds will run well on the Pioneer alone...can you think of any good 4 channel amps that will be small enough to fit under front passenger seat too...thanks for your help