Ron,
In my 240z, 3:90 diff, at Road Atlanta I only use 3rd and 4th. Savannah was the same with a 3.73. At CMP, I ran a 3.73 diff and used 2nd, 3rd and 4th. 2nd was way too low, had to shift out rather quickly or hit the rev limiter. I never tried the 3.90 at CMP.
A 3.73 had 2nd too low for turn 7 and 3rd too high. The 3.90 was just about right.

A 4.11 at Road Atlanta can lead to valve spring problems in a legal 240z. But its great in turn 7.

A 4-speed is a simpler rebuild (less moving parts and fewer gears)

The less I have to shift, the less time I lose shifting gears. Just my 2 cents.

Tom