Hi! I own a 2003 Utopia 185 with the Merc 240 EFI. I have been using premium gas (octane 93 or so) ... but saw some comments elsewhere that I should be using 87 octaine (regular gas) ... the Merc manual says 87 MINIMUM, but no warning not to use higher octane. Any reason NOT to use higher octane (other than $$$)??. Thanks!