I am running a VXL system in a Rustler with the stock traxxas 48p spur gear.
I have found that I burn through regular alloy Robinson pinions fairly quickly so that the one side of every tooth is flat. This makes the gears louder and the spur gear then wears out much quicker. I burnt through an aluminum 17t Robinson pinion in about 15 runs.
Traxxas pinions have held up very well.
The only pinion I have found to match it is the Robinson Racing "Absolute" pinion; I have at least 30 runs on the 16t and it looks like new. (Smaller pinions wear much faster because of the tooth profile and the fact that they have fewer teeth to go around).
http://www3.towerhobbies.com/cgi-bin...?&I=LXEX72&P=7