My last rebuild I went with the sport 700's.....the GTX were just coming into their own, if had waited on the purchasing, probably would have gone GTX, but since new technology has come out, the 700's have gone down in cost over the years. When I got into the TT years ago the 700's/28r's were it, unless you were the most aware mechanic out there. Last SZ dyno tune in St. Louis a friend had the GTX....there is a difference, but if you are going for pump gas....depends on your wallet...