Dare say that's as fast as its going to get on snow.
on concrete u will get closer to the theoretical top speed...but u probably will never hit it....
don't worry about ballooning to much... I suspect the voltage drop cancels that out.
id recommend re-thinking the setup
My LCG slash set up for a carpet off road track goes faster... its running 23/87, 35a esc, small 380 3900kv 2poll motor. on a 2s lipo with 2.2/3 jc subcultures...
for speed... u have a 540 low kv 4 poll motor.... it wouldent even be braking a sweet on that gearing and voltage....
Id recommend gearing up and/or going to 3s