As far as I know, they still haven't release IPS for the repower market yet. At last year's Miami show, the Volvo people told me it would probably be done for the January show. Right now, they're having a hard time keeping up with the new boat market, esp in Europe...
talk to a Volvo mechanic down here and he told me that if I plan to do that, the first thing I should do is reinforce the hull in the area where the system will come out.
Hueso, he's right. The production boats I;ve seen with IPS have very specific schedules. If you think thi is an avenue you want to pursue (and I don't think it's the right application in your case), your best bet is to go see it in person...
Although I probably wouldn't opt for this type of drive system for my 31, however, if I did, I would probably go with Merc's version where the props are pushing instead of pulling through the water. I like the idea of at least getting a little protection for the props by the skeg on the drive.
CMP, if they like it in Europe it must have an unseen problem. If you hit something with those props and the system breaks off, how long do you think the replacement will take. If they give you a 10 year warranty ok, but the cost to replace same must be significant, plus the loss of time using the boat, haul out and blocking up.