Matt,

I agree with you, sounds like you have the 86-87 speaker config., with respect to U.S. cars. The 88+ (US Spec) cars have a 5-1/4' in the door - it helps a bit. You may be able to purchase a repacement 88+ door panel, but it would probably be a pain to wire, etc.

The most expense MBQ's are like $800/pair or something, is it worth it?

__________________
2003 S500 Black/Charcoal
1990 560SEL 61k Arctic White/Grey

SOLD:
1988 420SEL Black/Palomino Sold @ 85k
1987 420SEL Midnight Blue/Grey
1986 420SEL Diamond Blue/Grey
1983 380SEL Champagne/Palomino