I think it should for sure be legal in MW SS, I'm on the fence about ST GTU mostly because it essentially puts an end to any hope that a mildly tuned SV could be competitive there.

There are many more SV's in this world than 848's and I would like to see some classes in the MRA where a SV could do well. Currently

LW GP - SV killed by TZ (unless you're moham)
ST GTU - SV killed by 749R (unless your moham)
Nov U - SV killed by 600's
and so on.