I've had a D5 in my buggy for over 3 months with no problems, tunes easy and is starting to become faster and faster with every race. I decided to try it in my truggy (removed alpha s852), and never looked back. Tome it seems the break in is short and sweet at least you can get a race tune sooner but you will notice the motor through more fuel become smoother and quicker.

All this talk about needles didn't matter to me cause I tuned an hour at a time and never had any issues, maybe just lucky I don't know. But I agree that don't knock it till you try it and even then go buy something else the rest haven't had any problems.