I didn't mean to imply that your friend was ripping anyone off, sorry if it seemed that way.

On the Traxxas 2.5, I'd say maybe 1 out of 20 are good, maybe a little more, maybe less. I exagerated the 1 out of 100 comment, to make a point, about all engines across the board, not just the Traxxas engine. Example being, a lot of people in our group run, or have ran at some time, the Sirio .18 in their Maxx's. Of all the people that have run the Sirio, I think only two have had problems with them. Not saying their tuning is any worse than anyone elses, they might have gotten a bad seed. This is less common in the top end motors, since they are precision machined, but they are assembled by hand. A little too tight on this screw, there goes an O-ring. A little too loose here, air leak or even worse, point of entry for dirt.