I own both cars and frankly the R8 just doesnt meet expectations on a track while the G8X exceeds.
Is my R8 faster from a dig and a straight line (traps 130-131)- yes but the car just has never been truly track dialed from a chassis and dampening standpoint. Its an amazing street car IMHO with luxury inside and beauty on the out.
It sure has a brilliant presence though and the V10 exhaust note is worth all the marbles. Since Im not a track master, the R8 (my 4th) is a perfect low budget last normally aspirated 600 plus hp car standing (one of them).
Oh I love my G80- heck its my 2nd!!!!
Great job to the OP too---are you sure you are even matched with your R8 compatriot