OK guys, bear with the newbie... Getting an 09 crew cab (2500HD-Dmax) with the low level sound system. (Not Bose) Looking to upgrade that. Don't need to blow out the windows (I'm over 50) but I do want to HEAR my geezer rock. So, a woofer or two, some upgraded speakers and an amp. I have a crossover filter I can use. What is the most bang for the buck? And how to tie into the existing system? Is there a wiring harness in place to a woofer location? Tweeters? Does the head have an RCA output or am I going LOC? What's the best place to tie in? Pull the head? What's there and what takes advantage of what's there the best? I am 99% XM-radio so don't need any fancy CD players etc. Haven't taken delivery of the truck yet, so don't even know if it has an aux input, otherwise I'll use the ol RF as much as I hate it.... Thanks.