I've seen what running turbo'd Volvo's on regular fuel can do...for the .20 a gallon premium charge, it's worth my piece of mind.
Based on an average fill up of 17 gallons, I'm only spending $3.40 more for a fill up and I fill up about every 1.5 - 2 weeks, so at most, $132 a year more then I would be if I ran regular. The normal 7,500 mile interval service costs twice that much at the dealership, if I had to actually replace a clogged injector or have a engine servicing done because of running improper fuel, I'd be looking at $500 +.