Sav XL conversion options..6 or 8S?

I am running 10s with a 1515/2y in a Losi 8t and it was a big improvement over the 2.5d and 6s I was running. Iam using 2 5s 3700 packs this setup is too heavy I wany to run 5s 2500 packs to get the battery weight under 650 grams right now its at 950

Iam using the Hv110 ESC with a pistix adapter and it is as smooth as any MMM with the recent firmware and software upgrades, the only problem is no reverse or brakes