I have used 1257s 1258s and 1256s

the 1256 is not needed for 1/10, way overkill.

I use a 1257 in buggy for its speed. Theres almost nothing to turn and buggy is primarily non contact.

SCT on the other hand is a little heavier. Bigger wheels, heavier platform. In SCT it seems minor bumping is racing, even when there is noone hacking on the track. When there is a hack job on the track, the 1258 puts up with it, no ifs, ands, or buts.

1257 should handle a SCT based on what i see out of the buggy. The 1258 is there to take a little more abuse. Personally I think it feels perfect for SCT.

Not to mention, if you add just a little overkill, it should last quite a bit longer.