I have an '88 Westy and replaced the 4" door speakers with 5 1/4" Polk coaxial speakers.

Things to watch out for if you replace the door speakers:
1.) Window cranks
2.) Make sure the grill does not stick out so far that it hits the dash when the door is closed.

If I had it to do over I would consider fitting separate woofers lower in the doors and mid-hi speaker in the standard postion.

Probably the biggest sonic difference you can make is adding a subwoofer if you don't already have one.

Its a good time to add an ipod interface if you are replacing the stereo.

Todd
'88 Westy

Where is the best place people have found to mount the CD changer?
I placed mine behind the driver's seat on the cabinent - but it is very awkard to change the cds while in the car.