Think of the 9L as a hvmaxx in terms of power and speed- in all the videos I've seen they are very comparable. Only difference is the temp/ efficiency as pointed out, so careful gearing and a heatsink clamp is definately required.
Option 3: Get some banebot 550 motors- they are the same power and speed as stock titans, but much better built and will last more than 30-40 runs before melting or falling to bits. They also only cost $5.45 each...
http://banebots.com/pc/MOTOR-BRUSH/M2-RS550-120