did mth make 3 versions of the S2 tubine?

Yes,MTH has made three versions:

The early semi scale Railking with either whistle or PS1

The Railking Imperial which is the same Railking engine with PS2 and additional detail.

And the "Bantam" version which is much smaller and handles 027 curves-similar to the Postwar Lionel 671/681/2020 turbine.

MTH has never made a full scale or "Premier" S2 turbine. Lionel has offered two scale turbines and 3rd Rail one. Current train shop rumors indicate that you will see a Legacy equipped scale turbine fairly soon as well as several other Legacy scale locomotives.

Ricky

was thinking on getting the semi scale version if it looks like the one on the pic at mth? I'd just got the 3rd rail and it would need upgrades with smoke unit and need sounds..dont know if it would be worth doing that to the O gage 3rd rail?

The Lionel Scale Die-Cast Turbine was a actually joint Mike Wolfe/Lionel project, as were several Lionel scale-sized offerings before Mike started MTH Electric Trains as an independent producer. I believe Lionel owns that tooling.

I'd like to see MTH release a scale die-cast S2 with Proto-3.

which lional tooling? the semi scale?

The 1991 Scale-sized with RailSounds and the follow-up version done with TMCC.