ORIGINAL: JUCD VPR
Oh hell yes there is a difference then stock, in an e-maxx probably a good 4-5 mph for SURE. (just a guess) MAYBE more?
THEN go buy yourself a good set of 7 cell batteries and you'll pick up ALOT of speed with that combination!
You can't run two 7-cell packs on the stock E-Maxx ESC can you?