I don't plan to run rear steer, but I would like dig. I will be running 3s lipo. I have a bunch of 3s 1600 and 2200 packs for my airplanes, so they should fit the bill.
For a servo, I have a 7955tg. The UBEC isn't adjustable, but it is factory set at 6V I believe, so it should get the job done.