The X mod tightens up the bass and gives it an upper mid push. Reviews have said that folks pretty much love it and it makes the module a keeper.
On the SL2, it's just 1 additional cap and 1 cap swap. I just don't know EXACTLY what parts are changed for doing it on the BMAN.
In its stock form, the clean sound is fat, but the problem is, the overdrive is too (and not in a good way). Like everyone else has mentioned, it's really loose. I'm looking for that gritty, Tom Petty (Last Dance w/Mary Jane) overdrive out of it, if possible. That song has that midrangey twang that I love.