I have a 2015 Mazda 6 Touring with 110,000 miles. I had to replaced the drive belt tensioner at 70,000 miles because it was leaking. Yesterday while I was servicing my car the tech said that the belt drive tensioner and serpentine belt need to be replace because of leaking in the tensioner. I declined and will do it at another time. The first time I did the replacement I went with OEM. Should I go with another OEM or Aftermarket. I don't trust the OEM tensioner from Mazda. Also the dealer wanted $700 to replace tensioner and serpentine belt. Any suggestions.