Hello!!
I drove it after upgrading from Big Rock 3S to 4S.
4S have different powers.
Hobby Wing series
Transmission MAX10 SCT 120A
Motor 3660SL G2 Brushless motor 3200KV
The price-performance ratio is good.
There is a slight heat cut phenomenon, but even if the pinion is lowered a little
Speed doesn't seem to be a problem.
Currently it is a pinion gear 15T.
It's a fun little car. ^^

Arrma Big rock crew cab V3

-Part upgrade-
ESC : Hobbywing EZRUN MAX10 SCT 120A
Motor : Hobbywing EZRUN 3660SL G2 Brushless motor 3200KV
Tire : Pro-Line Racing Trencher HP 2.8" All Terrain BELTED Truck Tires Mounted, AP6336 6x30 to 17mm Hex Adapters
Battery : DXF 8400mah 120c 4s
Gear : 32DP Motor Pinions Gear for 5mm shaft - 15T
Shock :  GPM Aluminum rear heavy-duty adjustable damper (front 102MM, rear 115MM)
Whee Nuts : Aluminum Wheel hubs 17mm Hex Nuts

Runtime : About 15 minutes

Hi where u from bro