Racing Brushless Setup

I just finished my electric revo and the drive abiltiy of it is middle of the road. Here is my setup:

Feigo 9l
Warrior 9920 Brushless Car Controller
11.1 v

Top speed is insane and run time is great as well.

If I went a 10l or 12l would that make low speed driveabilty better and jump up to 14.5v to make up the differance in more turn motor.

It also seems to cog a little at low speeds.

Is there a better speed controler out there? Maybe a Quark 125b?