I own a 2005 G35. Recently I had a G37 loaner car. The car was really fast and could easily spin all thru first with VDC off. The G37 would also do 2 gear changes going thru an intersection. The 7AT is geared really aggressively, even more so than the 6MT. The VQ35 and the VQ37 have similar torque output so I wondered why my car didn't have that off the line snap like the G37. The G37 has much much more gear torque (gear ratio x final drive ratio). Here is a chart I made showing gear ratios for all G35s and G37s, 5AT, 6MT, and 7AT. I also included in there calculations for people doing differential swaps. I have a 3.3 and was thinking about doing the 3.5 swap, but after making this chart, I will do the 3.69 swap. Swapping in the 3.69 will put the gear torque for each gear closer to 07-08(sedan) 5AT gears. The 7AT has too much gear torque and too many gears in my opinion.

 

Nice chart. Basically going from stock 3.357 to 3.692 you will be putting 10% more torque to the pavement, but hitting max rpm in each gear at a 10% lower speed.

 

Your chart is wrong on the 6MT - It has the 3.53 FD not 3.692

 

U right the 03-06 6mt does have the 3.5
the 07-10 6mt has the 3.692

 

Keep in mind that the G37 sedan weighs about 200lbs more than your 1st gen, the tires are nearly .6" taller, and the powerband is significantly higher. All this equates to need to increase overall gearing in the 2nd gen cars. There's no doubt the G37 is a faster car, but I think a 3.7 gear set will be a bit overkill for a VQ35 with a 5AT in daily driving. Increasing gearing definitely improves the seat of the pants feel of acceleration, but it is possible to overgear a car to the point that it's slower in the 1/4 mile.