I'm getting pretty great mileage 2.2-2.4 so far, but I take loonng trips.
On the lake trips I always hit the auto gas station and that saves me some money, but on the long 300 mile ocean trips I take I'm stuck finding docks, and anal rape only begins to describe what they can hit you up for premium at 50-80 gallons a throw.
The only annoyance other than the initial upfront "body slam" pricetag of the Ilmor Im running is that it calls for 92 which isnt available period on most water so I have to find particular gas docks and on the ocean that can be a pain. Im told the ilmor ecu is really good and will retard the timing automatically blah blah... and that a tank of 89 wouldnt be the end of the world, but Im trying not to go there.
The guys running race gas in offshore rigs completely mystify me, but my definition of "offshore" is likely different than most of the guys in this forum.