If you are not looking for huge booming bass, but tight, accurate bass, consider this option:

The factory speakers are about 8" in the rear deck. Put a set of free air subs (I happened to find the Sony Xplod 10" work great) mounted from the bottom on a TIGHT FITTING mouting board (of 1/2" MDF) firing through the stock holes (a 10" sub has roughly a 8" cone)
The mount board must be securely fastened to the rear deck from the bottom.
The trunk of the CLK is very well sealed and the seats are solid so there is very little lost sound to resonance cancellations.
There are several small holes that should be sealed (around the trunk hinge mounts, etc) but do not seal the vent holes at the very back edge (by the glass).

This way you don't lose trunk space, and it is a very clean install.
If you get the right free air driver, you (and everyone else, trust me) will be amazed with the bass.
Also, if the dealer intends to fire subs against the back of the rear seats, I suggest you tap your knuckles on the rear side of those seats. You will find they are very solid. Difficult to pass sound through, and if the subs face them, that will alter the bass (perhaps in a negative fashion)

By the way, how do you like your Yamaha ? What year is it?


[This message has been edited by trent (edited 10-17-2000).]

[This message has been edited by trent (edited 10-17-2000).]