In the vid I would agree with the 30mph range.
Sounds like you have stepped it up quite a bit though!hehe
If your doing 55mph now on 2S lipo I would think it would go over 60mph with 100% epa and maybe a couple of teeth up on the pinion gear? But the tire diameter will limit your overall speed.
Issue will be keeping it on the ground now!
I have seen RC18T's running 3S lipo and Mamba 8kv and they are completely krazy! They were running foam tires and would pull wheelies at 50mph + !!!