The only "amp" I've seen under the speedo is the power brake booster that 
'amplifies' my foot pressure.  Is there enough room for anything under there, 
with the brakes and clutch?

I put little blaupunkts in the original speaker holders, and they are OK.  
Adding a pair of larger speakers would certainly increase the fullness up front. 
 It's your cash, so it's your call.

Did you wire the rear speakers yourself?  Some vanagons that had factory 
speaker wires installed used a common ground wire for both speakers, and many new 
stereos don't like that too much.  Have you buddy at Circuit city test each 
individual wire and speaker, and check the output of the stereo.  And have him 
show you the 'amp', too.

My 2� worth

Bill Marshall
85 GL Tiico "Pandora's Box"
Aurora, IL