Hey guys. So I'm looking to put a mid grade system in my 2001 2500hd crew cab LT. While I know the basics things still can get sort of confusing to me so I'm looking for a little advice. For the obvious question of budget I'd like to keep it under 500 if possible. I know "you get what you pay for" but I was hoping I could get a good clear sounding system for this budget- I don't need anything showy or something that will be heard blocks away. Just something that can be loud when I want it to be and not be distorted- handles highs and lows well and hits moderately hard. Ive been looking on Craigslist to try and find a good deal on stuff but I don't know what exactly to look for with regards brands etc. also don't know what sizes for subs would sound best in a crew cab. I already have a dual 7in touchscreen flip out headunit which I was planning to keep and use- so I'm not too worried about headunit unless that one is terribly incapable which I doubt it is. Speakers Im thinking mid and tweeters combo since I'm putting subs in the back. Ive heard alpine makes good speakers? I'm not entirely sure how many speakers there are though.. (I just got the truck Monday so bear with me) obviously there are at least 4 - 1 in each door. But are there tweeters or something located elsewhere that came stock that I should also upgrade? The things I'm most shaky on are sub boxes and amps. I was thinking 2 10 or 12inch subs- I've heard it said there's no need to put rear speakers in if subs are back there? Also are the boxes they make that have subs and tweeters all already in them worthwhile? and finally how many amps do I need and how many channels? I want to amp the subs and speakers. Oh and the other thing- I have two batteries in the truck. I know the second is for snowplow or whatever auxiliary stuff. But I haven't had it hooked up. Will the alternator charge it if I do hook it up? And should I wire my system to that battery or to the main battery? And will I need to upgrade my alternator. Lol that's a lot but any help would be much appreciated. Thanks guys!