I have a 2,110cc coupled to Rancho's IRS 3:88 rear with the following ratios:
1'st = 3.50-somethng
2'nd = 2.06
3'rd = 1.26
4'th = 0.89
I used to have a 4:12 final up until 3 or 4 years ago and went to the 3:88 to get my highway revs down off the ceiling. I used to be over 3,500 at 70-ish mph with the 4:12 and often found myself sitting around 4K rpm chasing down other 356 drivers.
Now, with the 3:88 it sits at 3,200 for 70-ish mph and when I get up to 4K it's takes no prisoners.
3:88 Pros: Lower highway revs (actually, lower revs in all gears), better gas mileage, less of a "stump puller" in first gear (I can make it across an intersection before shifting).
3:88 cons: Slightly less acceleration/torque in each gear, slightly less "oomph" in third while canyon carving so I might drop into 2'nd for a few seconds at times in really curvy roads, but most of the time, stroking between 3'rd and 4'th is fine and I find myself sitting in 3'rd gear most of the time on quieter back roads. This was most noticeable the first few drives with the 3:88. After that, you just accept it as it is. 3 grand rpms in 3'rd gear is a sweet spot for me.
Your transaxle, in every gear, is running higher ratios than me, so expect your revs per gear to be lower than mine, but should be mitigated by the larger engine displacement and torque, to some degree. You should expect some 2-3-4 stroking in the canyons, too, depending on terrain. Not a bad thing, just is.