I have a 2006 Chaparral Signature 290 with 4.3L OSi Ocean Series engines and XDP drives. I had a bellows lwak and had water intrusion on my port drive last July, less than 1 year in the water. Volvo replaced the drive, gimble bearing, drive shaft and u-jounts under warranty.
I just had the boat hauled after a full year in salt water. The drives looked great, zincs great. The service guy just called and told me that both bellows (the supposed new ones) had leaked. No water in the drives, but both sides will need new u-joints, gimble bearings and bellows. he also found that the inside of the bellows was rubbing against the u-jount when the drives are trimmed to normal running angles, and was eating up the inside of the bellows. He thinks it happens because the hose for the engine water intake is pushing against the bellows, causing it to rub on the u=joint. He has a call into Volvo to see if this is a new issue.
I hope these bellows problems are resolved, as the XDP drive is a great idea and works great when it doesn't leak...at least I would expect Volvo to extend the warranty on the drives at least another 4 years as a good faith gesture.