It is probably not an XFI. The XFI is clearly badged and the engine has a different cam and computer from the other models.
The best way to set the timing is to first read the How To from TeamSwift here.............
http://www.teamswift.net/viewtopic.php?t=18091
I would set it a 8 degrees advanced and then test drive it. If the engine starts to ping under load, then retard it to 6 degrees. Sometimes you have to play it by ear to get it just right.