Bought one and have run a few times and have put it through a dyno, here are the results.
Before V2 endbell
32,000rpm @7.2V
6.4 amp drawn
After V2 End Bell
30,000 rpm
3.4 amp drawn
So here are the running the motor at the track results.
Before the endbell the Monster was as any monster should be.
After the endbell I noticed that the top end wasn't as sharp, but the low end had more punch. How much more is marginal. I wouldn't use this endbell on large tracks, but for tight small tracks the endbell would definantly bring down your lap times around those corners. Also though with the endbell there will be one greater advantage. LESS MOTOR WEAR. So really it is up to you and track you run on. I will keep mine for some tight tracks,
Just my two pennies,
Stephen <><