Track and road comparo: FR-S/BRZ/GC/MX-5/GTI
 

It's old - done last summer - but I just found it and it does not seem to be discussed anywhere here:
Auto123.com - a big auto site in Canada - ran a 2-part comparison on these five (the GC was a turbo R-Spec). Part 1 was a road test, part 2 a track test. Overall winner was the BRZ.

This is the first test I have seen that included the GTI. Relative car ratings are quite similar to those of Randy Pobst and co. in the MT comparo for the shared cars.

They stated that the FR-S had just slightly better turn-in and a bit less body roll than the BRZ, but found the 'Z to be less harsh, more compliant and provide a better balance between track and road driving attributes.