STAY AWAY from this fraudulent business. I paid for a "Stage II" complete overhaul of my Continental 0-300-a engine inculding NEW Titan CermiNil cylinders. No tags were returned with the new parts. I called and asked for the tags and was told they would send them but they never showed up. They stopped enswering phone calls, and emails. I even sent a registered letter which went unanswered. After 158 hours SMOH, compression in 3 cylinders were at 50, 55 and 25 over 80. I sent those cylinders to an independent shop only to discover they were not only, not new Titan CermiNil cylinders, but had been bored over .015 which is the legal limit. This indicates they had been overhauled twice. All three needed new exhaust valve guides, two needed intake and exhaust valve seats. the valves were reground.I contacted Ron Monson (owner of Performance Engines) and told him I paid for new and got overhauled. He said they would refund the difference in price but no longer had the records. I sent him copies of his invoice along with copies of the independent shop's report. Once again they stopped answering phone calls, and emails. No refund.After another 38 hours the compression was down in the 50s again so I replaced those 3 cylinders with new. 196 hours SMOH.At 371 hours, a valve stuck in one of the remaining cylinders so I replaced the remaining 3 with new.STAY AWAY FROM THIS SHOP!