I just wish I can find some stock 240 smoke nose cones again .
From what I understand about using different kinds of orings, they just wear out less quickly than your usual BN 70 rings. I've yet to hear someone get noticiable performance changes on a macdev marker just by switching types. At best you can say they take care of some sealing issues, but it's mostly with orings that are metric.
Also because of the o-ring composition, you might have re-break in your marker even longer.
There has been talk on PBN of the DX getting 1800 rounds and increased smoothness due to less pressure needed to shoot the ball, thanks to X rings. I figure I'll try it for 5 bucks and if not I can always switch back, as it's only 5 o rings lol.