I run a Kenwood tape deck, and some 4" duals with bass blockers in the dash, and some old school MTX box's with upgraded Fosgate 8" Series ones behind the seats. And a cassette adapter from my MP3/IPOD. Works good, but I do need a little more power. Sounds good, until you roll the windows down. I just haven't gotten around to installing my 20 year old Sherwood Tri-Way amp yet. At 320 Watts, it's almost too much for such a std cab. I'd like to find a 200 watt amp, and half the size. The newest items are my dash speakers and they are 5 years old.
I wouldn't spend a ton of money. Especially, with all the thieving going on, and we just beat our rigs. I've seen way too many guys with $1000's invested in a system, only to have water and mud short out their amps, and rot out the foam/paper in their speakers. And the press board speaker boxes fall apart/mold when they get wet.
