Hello and welcome Patrick!

About the cans:

http://www.xt660.com/showthread.php?t=7299

OTR have had them for a while and shipping isn't that expensive so you UK peeps can get them there. Titanium without cat 849€ + shipping, if you plan to go serious offroading take the steel without cat version for 699€ since titanium exhausts have a tendency to crack with too much bump and grind.