I swapped in a 3.5 in the G a long time ago and around town it makes driving way more fun and it's a direct swap. But on the freeway it's isn't a plus, at 80 (legal highway speeds here in Texas) the G's laboring at 3200 rpms and gas mileage sucks. For comparison my stock GTO with the T56 6 speed at 80 is lazily cruising along at 1600. Plus it gets significantly better mileage. A 3rd gear drop and full throttle at 75 to pass slow drivers produces massive joy and giddy smiles lol.