I have the Hollywood Krautster II special run that Mesa Hollywood did. It's pretty much the same except two humbucker e instead of having the P90 in the neck. I decided I wanted this guitar to have P90s, so I bought a set of the Bareknuckle Mississippi Queen hum-sized P90s and put those in. The guitar sounds great! In the bridge position you get a great ZZ Top kinda tone and mixing the ne k and bridge sounds exactly lik the intro to Stones "Brown Sugar". For reference, this is in the Plexi-ish channel of the Cherry Bomb (the amp I sell). In the heavier modes of my amp, the guitar sounds really great as well. P90s handle higher gain better than I thought they would.
Only caution I'd give you is that the necks are HUGE! Really fat necks, so if you don't get along with that, you are going to hate these. Personally, I'm fine with the fat neck profile...
Also, the original humbucker are really nice as well. Low output PAF style - they sound great and I'll probably use them in another guitar. There was really no need to change them except I wanted to try some P90s...
Steve