I'm not sure since the S950 doesn't have any of the vocal / choir / synth / pad & Sa2 sounds exclusive to the T4 it was difficult to tell what engine it's using, it does seem to have the warm sound of the T4 although I no longer have the T3 to compare it with.

The majority of the sounds within the s950 are in the T3 with exception of a few guitars and some kits so it's a closer comparison to that than the T4 I thought.