In the latest issue of Motor Trend, there is a comparison test of the Audi R8 V10 vs GTR. The GTR posts some crazy performance numbers (as usual) and tears up Willow Springs (1.55 mile course).
Additionally Motor Trend posts up their Willow Springs track data. The 2013 WRX Special Edition (no different than a standard WRX) actually posted some very decent numbers. It out ran the following cars:
2013 Subaru Impreza WRX Special Edition 1:27.4
2011 BMW M3 Coupe 1:27.7
2011 Ford Mustang GT 1:27.8
2013 Ford Focus ST 1:28.4
2013 Ford Mustang V-6 1:29.1
2013 Hyunda Genesis Coupe 1:29.1
2013 Ford Focus ST 1:29.3
2013 MazdaSpeed3 1:29.5
2013 Subaru BRZ (Long Termer) 1:30.3
2013 Subaru BRZ Limited 1:30.3
2013 Scion FR-S 1:31.2
2012 Volkswagen GTI DSG 1:31.5
2012 Mazda MX-5 Miata 1:31.9
I can only imagine the WRX's improvement with a proper alignment and stiffer shock dampening.