It actualy is a band switching mod, according to mods.dk.
I have purchased the diodes, and am going to send it off to Beltronics in 
new hampshire when money and health allow.
I have a friend who has used them in the past.  I gave them a call last 
year, and the typical rate for this mod and a complete re-allignment was 
around $200.00.
I also plan to have the inrad 3 khz  roofing filter for hf installed. 
Evidently, the 2000 uses only one roofing filter, a 15khz used for am, ssb 
and fm.  This mod installs a 3 k filter which is switched in for hf am, ssb, 
and cw I think.  Not sure about am.
Some time, I'll dig out the formula and do the math for the improvement in 
s/n between a 15k bandwidth and 3k.

I'll also dig up Beltronics info and the inrad filter info and post them.
Not sure when this will happen as I jut got home from a lower baack surgery 
yesterday.
73 all