Our Yamaha owner's manual simply states "Unleaded Fuel" is the recommendation. However, like in your case, Carts and Clubs (perhaps the same dealer where you got your cart) suggested using higher octane fuel for several reasons: first, to lower the 'stink' factor that is produced by the engine, and second, octane levels drop over time as fuel sits. Starting out with a higher octane fuel will net you more octane down the road versus starting with regular unleaded. To me, that part would be a non-issue if you use your cart on a regular basis - would only make sense for carts that sit unused for longer periods of time.
Also, the dealer recommended the Marine Formula/Ethanol version of Sta-Bil over the conventional Sta-Bil fuel stabilizer. Here's what the manufacturer says about their product - draw your own conclusions:
http://www.goldeagle.com/assets/news...am_%282%29.pdf
I've always used the conventional Sta-Bil in the fuel tanks of stored vehicles, etc. with no fuel related issues for years - but that's in OH. Maybe the issue being addressed by using the Marine Formula in carts in TV is based a lot on how humid it generally is in FL.
Personally, I feel the cart dealer knows a WHOLE lot more about golf carts than I ever will. So when they're recommending something - and not trying to sell me that same 'something' in the process - I'll listen and heed their advice accordingly.
Bill
