first, indash CD players sound very, very good but, even the best of them will skip while performing radical ariel manuvers. They don't do to hot over the wash board either. i had a Denon in my baja when i went down to mex. i finally got it to skip by hitting one of the san tomas speed bumps (8" high) at 35 mph. It did really well in just about everything except wash board. it didn't skip on half of the jumps, we were impressed.
i can't listen to music when i'm off-roading, though, i need to concentrate on what i'm doing. music is for pavement and dirt roads that don't make the cd's skip.
Cassettes would be a better bet if you can listen to music while off-roading.
amps are a necesity. your baja is loud. you want the music to be louder. even though head units have built in amps they are not powerful enough to overcome the noise of an average vw let alone a baja with a stinger.
mounting amps under your seats may not be a good idea if you go mud bogging at all. you get stuck....water seeps in....amps get flooded/ruined. i'll leave it to you to figure out where to put them.
speakers. my personal tastes here....i don't like speakers in the front. i like my music coming from the rear. all this business about stereo imaging, etc. is pretty much a lost cause in such a small vehicle. if you put speakers in the front doors the drivers side will be half as far from your ear as the passenger side. it just won't work. the *best* place to put full range speakers is behind the back seat. build a sealed box that fits there perfectly, find a way to secure it so it doesn't fly around while jumping. put some quality 6" x 9 " speakers in it (i'm partial to Polk Audio), point them straight up, toward the rear window. the sound hits the window and bounces toward the front of the car. give them some juice, like 50 watts each. this will be nice. subwoofers have to go behind the rear seat too. but there isn't much room. you could put a pair of 8" or 10" subs back there but then you couldn't put full range speakers there. quality 6" x 9" speakers with plenty of power will produce decent bass response. i'm more into accurate music reproduction than vision bluring bass anyway.
so, all you really need for a kick ass baja stereo is your choice of head unit, a sweet pair of full range speakers and an amplifer to drive those speakers.
So what do i have? well i have a Sanyo cd player (it was half price), a 35 watt x 2 Profile amp, a PAC "tri-way" crossover that allows you to run a pair of full range speakers and one subwoofer off of one amp, a pair of 5" x 7" Polk Audio speakers, and a 8" Pioneer sub. 35 watts to each Polk above 100 Hz and 70 watts to the sub below 100 Hz.
it all sounds pretty good, for $ 400.
