Thanks Greg, that is very helpful. The GTI has a 0.838 5th. Thus, your numbers would be equivalent to my running an imaginary 3.99 in the GTI. I can get a 3.94 or a 4.23. Sounds like the 4.23 might work since you're not shifting until the top of the Esses (thus 4.23 not necessarily better than the 3.94 at WGI, but hopefully not top-speed limiting), but then again, ITS might see a slightly higher top speed than ITA -- even yours If I can get away with the 4.23 for WGI, I think it might actually pay off at Lime Rock and NHIS.

EDITs: Oops, wait a minute . . . Maybe I'm stuck thinking in Scirocco mode, which really didn't go much faster between the top of the Esses and the Inner Loop kink. Sounds like the 4.23 could still be too much (i.e., like you running an imaginary 4.70). Think you'd run out of gear there if you were using a 4.70 (i.e., do you think you're over 6800 at the end of the Back Straight with current gearing)?