I'd pony up the $$ for a think walled round driveshaft for the rear, and then a square tube for the front. If you do it right, vibes are reduced (I had my truck running 60mph in the snow in 4hi with no vibes as long as I stayed on it, and kept the driveshaft under load) You will get some noise from the tube, simply because there is a little slop between the tubes, so it'll click, but thats no big deal
