No, higher kv is higher RPM which is speed since voltage x kv =rpm. A 5700kv motor on 2S will turn 8.4v x 5700rpm/v = 47,880rpm. A 7000kv on that same 2S would turn 58,800rpm. Higher rpm is higher speed.

You get more torque with lower kv motors - these can be geared up for good speed.

Tmaxx is heavy - what size 3500kv motor - 1/8th or 1/10th? 1/8th would be enough (maybe too fast depending on voltage you're running) and the 1/10th won't be enough for the weight - it may be able to get it moving, but its going to run hot.