I just did a little playing around with the numbers and found that if we threw that 3.82:1 Miata 1st gear in our trannys, we would increase speed from 31 to 36 mph. If we used the 3.31:1 gear from they Cayman it would take us to 41 mph.

More importantly (to me at least) is the road speed at 3,000 RPM, which is usually when I shift to second:

Stock: 15 MPH
3.82: 18 MPH
3.31: 21 MPH

Too bad we don't have cassette type trannys so we could play around with this.