I have an Optimax, and between asking Warrior (who rigged it), talked w/shops and browsed the internet, I only use the Merc Optimax oil.
Plus, I always put Stabil in every tank.

I have nothing but good to say about Lowrance support. Linda Colt took care of my GPS puck issue without hesitation, and while you do have to be on hold for 20-30 minutes to get support, they work until your problem is solved. I needed a different ohm terminator for my LCX-25 and they are just mailing it out, no questions, just taking care of it. Lance is the support supervisor and he will totally helpful.