I run 23 inch alltrails on my G16 with a 7 inch lift kit. When I first got it on there the stock clutches would hardly get it over a rut. I got this clutch
http://plowmanscarts.com/hp_clutch-kits.html
from Don and a Comet 94c front clutch off of Ebay.
The cart will now go through just about anything. I mud with it ALOT and as long as you wash it when your done and keep them good and greased they will work great! With most of these carts the problem with power and tourque lies in the clutches not the engine.