I sold my Procharged SLB '13 last month to a guy that dyno'd it and then did OPG's. It was making 775whp and he sent me a pic of the factory gears.... they looked perfectly fine after 50k/mi.
Anecdotal evidence, but evidence none the less.
I run a 170 t-stat and E85. I drive on average once a week for about 20 miles and I haven't had any issues with oil or fuel contamination. Just make sure when you do drive it that you get the oil up to temp for a bit and you will be fine. I run two breathers.
I imagine all you would need is to wire in a 2nd FPDM or get a GT350 FPDM setup as they run 2 pumps returnless from the factory.
Have you discussed this with your tuner? Most want you to run a return system as its easier to tune.