You have an interesting approach.... your auxiliary gizmos: weight station and setting wheels cost a bomb but you go on the cheap side on the stuff that makes the car move. The servo you got for the vorza probably has less torque than the one it came with, for $12 bucks you got $5 bucks worth of servo and it’s most likely gonna crap on you at the worst moment.... I’d be aiming for at least 20kg but better toward 40kg given the 6s and the lead you got loaded on board. A shorter throw horn will help the torque but that’s another quick fix to cover the real issue. Buy nice....