Ahh now we're looking at the overal ratios. The highlights here are the first gear overal an the ratio between first and second (usally the biggest ratio).

You can see that with the Z33 + 4.083 you get a pretty big first gear multiplier. You're not going to put 350ft-lbs down through that without slicks. It would be pretty slick on a small turbo KA, but I doubt budget people are looking to do tranny swaps. The Z33 + 3.69 will give you right at 14.0 in first, which would be nice. The 3.69 came in later Q45's (97-01?), and Nissan Motorsports offers a 3.7 kit for the 350Z, but it's $$$.

The other point is the 1st to 2nd ratio. Take smaller number over bigger number, which will give you a number smaller than 1. Multiply by your redline (or 1st gear shift point) and this is the RPM you'll wind up with in 2nd after the shift. The Z33 gear keep the RPMs up into 2nd. This is what they mean by "close ratio", although this is just "closer". With a 7k rev limit and KA trans, you'll be at 4000rpms in 2nd after the shift. This is below the full boost threshold for a lot of 450+whp KA's. The Z33 trans will leave you at 4300rpms, which is better. These calcs are independant of final drive, by the way. Doing the division by straight gear ratios or overall (fd included) ratios will yeild the same number.

The J30 has a 3.93 FD and is bolt in.