My e-tec dealer said just put good gas and good oil in it and run it. I just about went broke running the Yamaha stuff in my old motor and didn't really see a benefit to it. You don't have much control at the pump, but you do over the oil you use. Run the best. I put 100 hours a year on my motor counting the winter down time but it still gets used in cool weather. I personally think the key to motor longevity, aside from the oil, is picking a comfortable operating range for the motor, not WOT, and run it there. Every couple of hours, I'll punch mine out for a couple of minutes, but most of the time I drive it like a human being, not like I stole it.
2015 Seaark 1872 MV CC Etec-90
Helix 12 CHIRP SI, HB 1199, MinnKota Riptide ST80/i-pilot Link, Bob's Hydraulic
Bitter Gun Owner