At the end of this season I think I'm going to hang a new outboard on the back of my boat. I'm just not sure what... The boat is a 99 Sylvan Viper, I'm pleased with the boat and I've finally got everything setup like I like it. It has a 150 Mercury EFI as the main motor now, the boat is rated for a 175 so I'm thinking about getting a Opti or Pro XS 175. Why should I spend the extra money and get a Pro XS? I don't need a 175, I usually only run my boat at 25-30 mph... just think it'd be fun to have the extra speed once in awhile. Is the 175 going to be any worse on gas then a 150 Opti? Anyway, it's a ways off so I've got time to sort everything out... Thanks guys.

You'll appreciate the fuel economy difference with any of the new Direct Injection motors, or 4 strokes over your EFI.

I'm not sure about the repower choice though. Typically you will find it's better to update both the boat and motor. Motors cost a bunch, and end up not making much of a difference on your market value when put on an older boat.

The 175 Pro XS has quite a bit better mid range power than the standard Opti, which is where you operate your boat from your description. It also rev's a little higher, and is a touch faster, and a little more expensive.