I recently installed a pair of Blaupunkt Overdrive 5 1/4" component
speakers (model ODca540) in my front doors and they sound and look
great.  (Although retail list is $230, I was able to pick them up for much
less on eBay.)

One neat feature of these speakers is that the tweeters can be mounted at
an angle, facing back towards the driver and passengers.  This greatly
improves sound quality, especially when mounting the tweeters where the
original 4" door speakers were located, as I did.

To install the tweeters, I removed the stock 4" speakers, carefully pried
the old speakers (and all associated black plastic) from the old grilles,
and snipped holes in the old grilles just large enough to accommodate the
new tweeters.  I cut a ring of black construction paper to cover the inner
surface of the old grille, between the tweeter and the edge of the
grille.  It was then a simple matter to attach the tweeters using the
screw-on mounting ring supplied -- then re-insert the old speaker grilles
(with the new tweeters) and attach them using the original screw-on rings.

Installing the 5 1/4" speakers required cutting a little bit of sheet metal
at the bottom of the door panel, but nothing major.  I also had to remove
the plastic "box" that covers the lower door hinge inside the door, in
order to make room for the speaker.  I used XTC 5 1/4" slim foam speaker
baffles, to protect them from dirt and moisture.

Overall, a fairly simple project and a very nice addition to the van!

Ray Reinhard
'86 TiiCo Westy Camper GL