Motor ESC combo question
 

I am racing Stock SCT 17.5 running a Losi 22 SCT. I am in the market for an ESC and was looking at the Tekin RS gen2 Spec as well as the RS gen2. I found I can get the ESC/Motor combo for a pretty good deal compared to buying separately. Now for my first question does the rotor size in the motor affect the torque? Tekin has two versions of 17.5 standard and RPM. The RPM version specs say it will have 200KV more than the standard motor. The rotors are 12.5MM and 12.3MM. Which version would be better in my application? Next is the ESC for what I am running now the Spec version of the ESC will work fine, does anyone have regrets that they didn't buy the the non Spec version?

I would go for the Gen2 RS rpm combo if its a hi speed track where you race or the torque combo if it's a short twisting track.