I'm also considering one of these for track duty, but worry it'll feel slow compared to my GTI.
The lack of torque is actually less of an issue on the track since you're almost always keeping the revs high at 4500-7400 rpm. The two are closer than you'd think in terms of straightline speed. When my FR-S was stock other than Sumitomo HTR-ZIII tires and mild alignment (-1.5 degrees front, 0 toe f/r) and my GTI was stock other than bfgoodrich gforce super sport a/s tires, I took them both to the same track. My FR-S was hitting 105 mph on the back straight. My GTI was typically at 103 mph. That doesn't mean the FR-S was pulling harder since it had significant mid corner and exit speed advantage on the preceding corner. But it did end up being faster down the straight as a result.
If you're a pretty good driver and can take advantage of the corner speeds (and braking advantage), the FR-S will be faster on most tracks in my experience.
Coming out of tight corners or driving on the street is where the GTI will feel much torquier.
Edit: Just saw your GTI is stage 2. Much different comparison there for obvious reasons.