Had my Gen3 on the track last Thursday and WOW!!!!!! How does one determine which ratio one has? I know in T12 at Portland, I could go down to second gear, but it was mid apex and I was in it for about 2 seconds so I was leaving it in third gear most of the time.

I have never driven Portland, but based on your comment that you were leaving it in third gear most of the time you probably have the 3.62 ring and pinion (which has been the standard for the 1.9). With the optional 3.85 in a GEN3 your gear selections around the track should be very similar to what you experience with a 1.9.

Sounds like the 3.62. Generally, I found the best power between 5,000 and 6,200. Going down to 4,500 was possible, but below that it felt slower or at least comparable than the 1.9 (didn't go below 4,000 based on advise from Enterprises) based on running around 1.9 traffic. Could run it up to the rev limiter (6,800?) in 2nd gear if needed (e.g. exiting T12 at Thunderhill). The difference was most noticeable in the places where the 1.9 was in the 4,000-4,500 RPM range.

Forgot to mention T2 (chicane) and T7 it was obvious that second gear was the gear to be in. And squirting out of those turns in second IS fun!!