Crutchfield is very helpful.
Their prices are quite a bit higher than you can find it elsewhere on-line, but their install kits,wiring harnesses and radio and speaker install directions & fitment guides make everything SIMPLE. I usually lay the new HU wiring out on a table and solder/shrinkwrap all of the connections before putting it in the car/truck.
I find the HU i want and get it cheap as possible (usually ebay), then get all the kits/harnesses from crutchfield.
