I had the chance to take two test rides today of the HyperMotard with the full racing system (side can).
First the full system doesn't look so bad on the bike and I think it fits more than the under seat plus loosing the weight of the stock system (felt like 15 pounds) isn't a bad thing.
The first ride I had my wife on the back and did that bike pull and it handled great moving in and out of traffic, it was hard to hear the bike though, as the screams of terror from my wife drowned it out but an awesome first ride. My wife said it was the most comfortable Duc she has been on (I won't let her sit on an ST) and after riding with her a few times by far this was the most enjoyable ride.
The second ride was solo and was fantastic the bike pulls and pulls and brakes very well and very hard (if you ask it too). The bike would still stop well with a single caliper and I might try that.
After taking the bike out I got a thumb up on putting a deposit on it, but I'll have to sell my 998.
I guess I'll have to change my user name soon.