Recently finished my system and I couldn't be happier. My truck came with audiophile components so it sounded decent in the first place. I can't put a percentage on how much better it sounds now. This is what I'm running: Sony XAV-72BT HU, 6x8 Infinity Reference components in front doors, Infinity Kappa 6x8s in rear doors, Kenwood XR-5S amp (80x4 rms + 350x1), and a Kicker 4 ohm SVC sub in the factory box, wireless backup camera that I ended up wiring because the reception sucked. At some point in the future I might step up to a bigger sub but for now the reload will do. I did all the work myself including the amp board. I appreciate all the information on this forum.
Put any doubts to rest about how much better decent aftermarket equipment sounds. There is no comparison. Here are some pictures of my set up.

 

Ive heard a lot of complaints and praise on this head unit. Im about 2 weeks from buying though. Anything worth mentioning? Is it really that slow to respond?