As to mods, etc. I am backed up about two months just like the Mesa service. The "3+" can be done to emulate the MK2C+ amp as well as possible. Also the 3++ mod, which gives the full on DBL plus leads sound when lead and R2 are both on together. Amnd when BOTH are off you still get the classic C+ clean sound. these are $350 and $450 respectively, and paid to me by check.
The 5 band EQ can still be installed on a MK3 as I have a few "blem" front panels still and all else I need to do it excatly as if original.
This is also a mod paid to me by check for $1000.