I run ring free and the fuel stabilizer. Dealership recommended both, and it was a heck of an investment so I figure why not? Little bit of screwing around pouring the crap in every time I fill up but not a huge hassle. I run the 175 SHO. I think around a little less than 150 hours so far and no issues yet (knock on wood) Still just a baby, these things should run for a long time.
I run premium with no alcohol. Seems techs I’ve talked to are 50/50 on fuel additives. I don’t run my motors hard. Generally, 3/4 throttle. But I do get some rpms with my prop pitch. Dealer has my brother sold on it.