Yeah just buy the single gear set for the xl.
http://redcatracing.com/itemdetail_p...p?partno=05126
That's part number 05126.
It'll be a direct swap. And then do what the others guys are saying and buy one of those hpi racing clutchbells.
[link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXLST8&P=7]16 tooth[/link]
[link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXLST7&P=7]15 tooth[/link]
[link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXLST6&P=7]14 tooth[/link]
[link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXLST5&P=7]13 tooth[/link]
The less teeth the more acceleration you will get.
Good luck.