[TheSunDanceKid]

first off that panisonic deck is awesome i remember doing an install a couple years back and that thing was pretty nifty spec wise its about the same as the 680mp i personaly like panisonic better then the pioneers in sound quailty and the pioneers can be a pain to navigate well the newer ones anyways
if your looking for sound qaulity crisp and clear and not sloppy id go with boston acoustics they are pricy but wont let you down and has some of the best sound out there specially if your going to put a 4channel to them not really for rap and what not but will still get great sound theyer line of subs also has some of the best bass if your looking for clarity and not just nasty sloppy bass
i have 2 of their g2 10" subs in my silverado have but out for the door speakers yet but i have had the 6 1/2 componets and 6x9s in my s10 sorry to say let them go when i sold the truck

ive worked at an audio shop installing for around 5years and mecp cert mostly installing pioneer alpine kenwood and boston out of the years id put poineer on the end of the list as for sound qaulity but still good sound im just saying out of those 4

pioneer decks also if you get alot of alternator whine the pre outs on the deck are junk when using a 4 channel and alot of the time you have to ground them out on the back of the deck if you deside to use one of the pioneers

if your looking for a 4channel id go with kenwood or alpine if you got the money and can find one a boston but they are expesive