As I said before in another thread, depending on your mods and power levels, and what you are using it for, would depend on what you want.
It seems the OP takes it to the track, so he needs to figure out if he wants more power or not before he decides on gear ratio. I personally think at 3.45 first gear is useless.
https://fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-ash4/428128_363008140396100_1352109031_n.jpg
I hope that FB link works.
Anyway, both of those are G8s I am on the right, my friend is on the left. I have the 6.2 LS3 he still has the L76 6.0. I have ported heads, 3.27 gears, and a mild cam, compared to his more aggressive came, ported and milled heads, and 3.45 gears. I am on stock 18s with 275/40/18 NT05s in the back compared to his CCW drag pack with drag tires. We both did gear swap within a few weeks of each other and it was our first time racing with the near gears. Before this race, I was at 12.1 to 12.2, he was at 11.8 to 11.9.
With the new one, I am at 11.83 and he was at 11.80, his best time. He even admitted, he should have waited on finding a good 3.27 gear as he had too much gear for first, but not enough to start in 2nd. 1st gear ratio is 4.07 (if i remember correctly)
4.07 x 2.92 = 11.88
4.07 x 3.27 = 13.31
4.07 x 3.45 = 14.04
Now lets compare it to say, a 94-97 Fbody M6, such as my brothers car
rear diff is 3.42 and 1st gear is 2.66
2.66 x 3.42 = 9.10
2.66 x 2.92 = 7.77
2.66 x 3.27 = 8.70
2.66 x 3.91 = 10.4
Look at those numbers. going from a 2.92 to a 3.27 would not be worth it, and a 3.42 which is stock is still lower than our first gear ratio stock. even the 3.91 gears are not even up to our stock gear ratio in first gear.
I really think you need to think why you want the gear change, if you want to just smoke your tires at 45 mph on the freeway, yeah go with the 3.45. If you want more usable power and a lighter feeling car, and a gear ratio.
Here is the final thing I will say though, If you like to drag race, you will have to think at what gear you will be in. If you are tuned and changed the shift point to say 6600 rpms, 3rd gear tops at 113, and 4th at 150. Well more than enough to get some power mods and not be in OD.
3.27s it is 101 and 134, Still good enough for me to never top out at 4th (i think even if I do supercharger, I will be in the high 120 mph). At 3.45 3rd is 95 and 4th is 127 mph. Right now, if I was at 3.45 I will be near the top of 4th, and going straight into OD with any power adder.
Anyway, it is up to you, but don't let people say, it isn't worth it on the 3.27s, I picked up 5mph and dropped .3 on the ET. Worth the 1k I spent on buying and paying shop labor.
