My mechanic had a couple of runs off the limiter (8K) and it bogged (2.1 & 2.2 60').
I went off 6-6.5K and managed a 1.85 and 1.75 60'. This is with 275/35/19 Kumho Ecsta's and twin plate DCS clutch. I'm thinking the rubber is too big.
Tried two-step on the street and it bogged also. Stock engine so I took the two-step off.
Have you ordered the OS88 yet?
OS88 is a two month wait, too.
I had a driveline spreadsheet with all the ratios for every available GTR box or gearset around...but I can't seem to find it...grrr.