Yeah. The VR-4 and MR are both intercooled twin-turbo machines, wheras the SL is naturally-aspirated. I can't remember exactly which models are in GT3, but there shouldn't be much difference between a VR-4 and a VR-4 "turbo". Both should be turbos, basically.
I believe Mitsubishi offered the difference when the car was made as a slight name change for when it was refreshened in 1998. One of them has a 6 speed and one of them has a 5 speed (and I'm not even sure about that), but otherwise they are mechanically similar.