same thing happened to me( 6'4" as well) First get a extended cab if you can. much more room for us. That is what I did after about a year. But to hold you over... I bought 8" subs, I still have to sell <img src="/forums/images/graemlins/smile.gif" alt="" /> but I had to make the boxes so they would fit. I did it wrong,(Fiberglass half a box) so my sug to you is fiberglass the back. I have alot of info saved on it so if you're intersted. the best that I used was a 600 watt 6x9 that ran off a sony 760w amp that I strapped with abungie cord right in front of the pass seat (bench). Pass. would complain a little but do they want a ride? <img src="/forums/images/graemlins/lol.gif" alt="" /> hope that helps.