Reef Racer2 Can't Compete W/Zig Zag?

[avwiz66]

I picked up a Reef Racer2 to race around with a friend's Zig Zag Racer but,
it just won't keep up.
Is there something wrong with my RR2 or are they just slower?
Anybody using any motor, prop, or battery mods that work with the stock esc on this little guy?