The 8 speed will be more forgiven in the 1st 3 gears
, but towing will suck with the V6 and 35's, you really should think about 4.56's if you're seriousy considering towing anything with 35's, day and night difference, i have a 6 speed Hemi crew cab with 3.92's and 35's, and while ok, the 3.92 gearing is still not exactly optimal for the tire size, but the Hemi helps a lot.
I had a Jeep Wrangler unlimited highly modded, and that sucker was almost as heavy as my Truck, but had 4.56's with 35's and the V6 pentastar motor, i thought 35's felt kind of ok with 3.21's (i upgraded to 4.56's couple of months after doing 35's) until i had the Jeep regeared to 4.56s. I would't run no less than 4.56's with the V6, and trust me, gears alone make a very noticeable difference, especially when you come from 3.21's, they're worth every penny and will put a grin in your face guaranteed. Sure regearing is not cheap, but 35's are not cheap either, i don't know how expensive is to regear this trucks, but i had my Jeep regeared to 4.56's for $1k OTD, and could use the same people to do the job if i was going to step up to 37's, as my choice for that size will be 4.56's..., don't fear the gear, it applies to any vehcile application.