Your sled motor and CVT should already be geared low enough for your buggy build.If you can find a cheap used Polaris ATV you can use the gear box to get reverse. A cheap 1/2 shaft solution if you can one find is old Baja65 like I found (whole buggy for $50 bucks!)They were sold at Pep Boys back in early to mid 2000. That's what I'm experimenting with on my Frankenbuggy now. I haven't found a cheap CV set-up yet either,used or otherwise. My opinion on swing arms is that location of the shock in relationship to the frame and length of swing arm makes a world of difference on the ride.Also the position of the rear tires in relationship to your butt contributes heavily to stability and comfort as well. Buggynuts/Krusekontrol (
http://buggymasters.com/forum/showthread.php?t=282) UFB builds shows that and Bigkid's (
http://buggymasters.com/forum/showthread.php?t=1083) sled motor on his Coolster is a good example of another swingarm set-up.Square tubing is FINE!! it's certainly is easier to fab-