Hy dude,
There's many possible upgrade for your propulse, here's a link for the
Racing high-speed motor. You'll need to change the ratio...for a good setup but it seems that you've got in this pack a 14-Tooth Pinion Gear.
For my car I choose a brushless conversion from Carson (micro dragster 6000kv with his esc). But with so much power (i run it in 3s) every dogbones have been destroyed in a few run, same for the diff's en co. Changed for 3racing metal diffs and gear. Next upgrade in the way is the Megatech aluminium kit (blue).
Hope this help,