I’ve done the exact same thing. Incredible how much difference a battery can make.

Ours has been mostly very durable, even with a hard skatepark life. About every 6 months we need to replace the driveshaft pinion that engages the rear diff. It’s made of horrible cheap metal and even slight wear makes it slip and grind. I’ve yet to find an upgrade for this part. Have you rotated the motor mount and changed the motor pinion for a 14t ? On a 2S, this bumps the top speed to a respectable 30mph