I use one as a practice motor, and it's great. I have an older Monster Stock Pro that has a pretty small comm, somewhere around .270, and this thing has a lot of RPM with the V2. Typically people say to gear up with the V2, but I geared down with this particular motor and it is nearly as fast as my best standard endbell stocker. I'm using either medium or medium hard springs with sprint brushes, sorry can't remember the springs. This is in a stock touring car, though I also use this motor in stock buggy racing for a series that allows the use of the V2 endbell in any class. I also used the endbell on a Core Stock motor in my MF2 in the same series, and it had good power, enough to win the B main in expert, and I hadn't raced truck in about 5 months.
The kicker is..... I've run that Monster for 20+ runs between cuts, with no loss of power I could feel, even after 20 runs. After the first 20 runs, I only cleaned the comm, didn't cut it, and after the 2nd 20 it only took a tiny cut to true it up, and the brushes are hardly wearing at all (sprints are supposed to go 3 to 5 runs, these have 45+ on them). My laptimes in practice are within a 10th of a second of my race laptimes, if not the same.
I've been pretty amazed with this endbell, and I'm not at all affiliated with Orion/Peak. I don't have to use up my strong stock motors in practice. The key for stock motors is not using hard springs, they will make the motor a dog (I tried those first and hated it). Medium or medium hard are the way to go for me.
I know this isn't the "popular" line of thinking on this endbell, but I don't think you'll be disappointed if you get one, plus you can probably use the same motor for long enough to save yourself from buying 3 new stock motors or arms, which more than pays for it. If you're looking for all out power, then it probably won't live up, but it's had plenty for me.