What batteries are you running? If you go lipo, you can probably pick up more speed, otherwise I recommend you replace both the motor and speed control with a brushless system.

I have recently bought a traxxas 2wd slash. And already wanting to make it go faster besides putting a lipo in it.

I have recently bought a traxxas slash 2wd it has a traxxas slash titan 12t brushless motor with a xl-5. I was wondering if I bought a new different faster motor if I would have to get something different than a xl-5.