rschoi_75

Those choices are ok, but it all depends on the track you plan to race at. I assume you will race in an open class, since you are jumping to brushless right away. The things you have now are best suited for a large track, 1/10th track, and so on. For most normal 1/18th tracks, you'll want a top speed of 20-25mph.

If you go brushless, I'd suggest something with a lower kv like the mamba 5400. People may disagree, but I think its more of a personal choice that need to match your driving style. I like control and consistency for racing. Ballistic speed runs and what not can be saved for bashing.

For the esc, I don't know anything about the dynamite taser. I use mamba 25's in most of my mini's. I like them because of the computer programming function, and constant software updates.

Batteries: all those will be fine. You will need to raise the battery posts for the one lanerbrainer205 linked in post 9. Again, I would personally use a 2s lipo for racing. Most tracks will not allow a 3s lipo in a race anyways.

The key to buying lipos is making sure that you get a high enough constant amp rating to provide your motor with enough power. You can figure this out using this: Amps = "C" rating x ah (amp hours). Amp hours is just the capacity (2100mah = 2.1ah). So a lipo with a 15C constant rating and 2100mah will provide 31.5 amps constant. Most normal 20mm diameter motors like mamba, tekin, c4, cobalt, etc. will draw anywhere between 12-25 amps constant. So these batteries will do just fine.