I have a few different motiv balls and will try to help. You can take a SX1 and give it a polish with some compound, not polish. I just recently tried that and am getting a great reaction out of it now. It is weaker than the SR2 by a good amount. I didn't care for the reaction I was getting out of my TR2, as it was very close to the SR2 I have. I took the TR2 to 1000 abralon and it is now slightly weaker than the SR2. It does however have a different roll to it. Where the balls with the sigma blocks (thats the S in SR & SX) have a little more POP when they make the turn, the Thrust core in the TX1 seems to be a little more rolly off the spot. I have found that my line-up of the SR2 lightly hit with a green scotch-brite is the big oil ball. Next comes the TR2 with the SX1 in third. There is about 3 boards difference between each ball on a typicl house shot. Hope this helps.