Oooh, I haven't magazine-raced in a while.

Maybe in a stoplight drag race, as AWD provides a huge advantage in that scenario...but where it matters - race track - GTR will be chasing taillights:

http://www.roadandtrack.com/new-cars/news/a27254/the-dodge-viper-is-going-out-on-a-high-note-setting-13-track-records/

While these are set by the current generation Viper ACR, the current "street" version of the Viper outperforms the previous generation ACR on the track, therefore I would still bet money on the Viper even against a modded GTR on the track.

https://nurburgringlaptimes.com/lap-times-top-100/

On one of the most challenging tracks out there, nurburgring, a 2009 Viper ACR (factory stock) still holds the #9 record while a 2015 GT-R is #6. Considering that 2013 and newer Vipers outperform older ACR models in both dynamics and power, a 2013+ Viper GTS could place itself in the top 5 on that track.