This isa copy & paste from another forum. Get in touch with Claudio or Where you bought the engine. That may be the best.

QUOTE:
With the translation help of a Italian FG member (thank you!!!), I sent a note to Claudio on Wednesday this week, detailing what I've found to date, performance improvements and the Bowman ring / rumours of thinner cylinder coating.

Claudio responded yesterday (great response time!!) with the following comments.....
* He stated that he has had a bad batch of rings
* He said he feels it's impossible that my M60 is overbore (ie: less coating thickness)
* He'd like me to send him the motor, exhaust, stock ring and Bowman ring and he will inspect and advise.

I have sent Claudio's response to Blaine at TopDawg and Blaine supports me sending it back.

I'm just awaiting Claudio's shipping address and will get it in the mail. This is likely going to cost me another ~$100.00 to ship to Italy, however I support the Mintor brand and if my motor can help Claudio for future motors or to improve the M60 engine, I'll do it.

It'll be interesting to see if mine is a dud or if Claudio feels my M60 is performing as expected. In the meantime, I have put my DLE55 back in the Pilot Edge and it is performing flawlessly with insane performance!!!