+1
I find that at louder volumes the EQ-less mark III's sound better, but I use my EQ always, mostly on the lead channel only, and keeping the R1 and R2 as a more vintagey tone. But the EQ is great on all 3 channels, and for Metallica style cleans and leads, it's a must.....
You can get one installed by Mesa if you got a great deal on one. I'm not sure how much, but I'm sure it's fairly reasonable...
There's plenty on ebay to be had with EQ's and simulclass.
ax. :twisted: