B&K M200 Mono Bloack and Musical Concepts Mods

I have a pair of B&K M200 Sonata monoblocks that need service. I'm planning to send them back to B&K Service for a "Tune Up" - whcih is likely to cost $100-$200 plus shipping assuming they do moderate parts replacement.
I was also looking at the Musical Concepts web site - specifically at their "LX Mod" which costs $499 for the pair. I don't want to spend a small fortune so am not inclined to go for one of their more expensive mods.

Here's my questions - is anyone familiar with Musical concepts Mod's, either on the M-200 or any other amps and can you tell me how satisfied you are with the results? Also, are there any other companies with modification packages you would recommend?

thanks in advance!