I have been using Redline 20-60 in the motors for year, Not noisy at all, Plan on using it this 2017 m-8 also. I have used Formula Plus in the primary and have not found anything as quiet as it. Also ran Redline Shockproof Heavy in the trans ,Keeps the trans quite and easy shifting also. Debating if the M-8 Trans needs it as I have a gear whine in 3rd and 4th may try it at the first service. Doc