Couple of questions on the 8ight T

Well I just could not pass on the 300 dollar 8ight Ts on Ebay that have been up as late. So I pulled the trigger and ordered one. I have the MMM and plan on going 4s Lipo (especially since I have a couple of 4s packs already). I have read other threads that discuss the Neu 1515 1y for the Losi Truggy, but not clear on if that it is best to run 4s or do I need something higher?
The other question I have is regarding the wheels, I just bash so I would like to use 40 series tires and Axial over sized beadlocks. Will that stress the truck out to much, I have seen lots of the Gorilla Maxx crowd running them so I think it would be fine. I would like to hear anyone that has experience with 40 series on a truggy platform.
Thanks everyone and Merry Christmas!