Longer swingarm makes turning radius wider, helps hold front end down if it wheelie happy. It has little effect for speed stability other than making them feel lethargic when going fast. If you pushed the spindles forward an inch with a-arms it will reduce the nervous feeling when going fast and not hurt your turn radius as much. If your in the woods Stock is best. Sand +1 front and or +2 rear. As PCS said can always shorten, I don't reccomend lengthening swkngarms in any case especiall if you like to jump.