I just finished doing the same thing you want to do. You need to make shims for the lower triple... about .020 I think. The upper triple will have to be replaced. You could have it bored out, but I don't recommend it due to the lack of quality of the metal. This summer I'll be selling uppers to convert Monsters with SBK forks. Since the Monster already has a 25mm front axle, you're wheel, speedo drive, etc. will bolt right up. One thing you'll have to check it the calipers.... I can't remember what year the Monsters got the 65mm caliper mounts on the fork leg. Just double check.. and let me know if you need different calipers, as I've got a few sets lying around. Oh, one more thing.. the front fender will not fit. You'll have to get a SBK fender.
It's going to be about $350ish for the production triples. I'll know something a little more in a few weeks. Forks vary in price....~$500. I usually have a good line on a set as people like to recover a little cash when they buy Ohlins R/T or SBK forks from me.
Pics will be up by this time next week... The Coast Guard is getting in the way of my maintenace that is left to be done!!