160 something last year. I was too busy watching the road when doing this but it was just past the 160 mark. And I dare not taken a photo while driving that speed.
I'm sure it can do more though. My slower Nismo 370Z hit 155mph pretty easily but bounced off the speed limiter. Maybe 170 something for the turbo FR-S? Just found out that 6th tops out around 170
This was done inbetween Houston and Dallas on I-45.