I also have a blue stripe, and recently decided to go with a head conversion. I had a friend ask me if I was sure I wanted to lose the portability of a combo, so I told him to pick the amp up one inch off the ground, and does it and just goes, "oh."
I got my head shell from George (gts on this board) and I am quite pleased with it. There is plenty of testimony to his work, you wouldn't be disappointed.
As to your question, it was not very hard to switch the amp over, but there were tricky spots with the fan and such. Mesa really crams the stuff in there, but it was kind of fun seeing how they put it all together.
I did like the sound of the combo, but I like my 2x12 vertical recto better, and that's pretty much what I always used anyway.
If you want a head, go for it!
