Don't count out the Infiniti. We just bought a QX60 for the Mrs., she runs regular in it with a tank every 2-3k of premium, so far haven't had an ill effects. Same went for a Maxima that we had a few cars ago, recommended premium for maximum performance, but always ran regular. Once the valves get to chattering too much she runs a premium tank and then back to regular for a while.
"Recommended" is one thing...in those cars, the ECU can control ignition and compensate for 87 octane. Cars that "require" premium, I'm not sure it's good for them to have 87.
So this story came to an end today. Here's how it worked out...
Before I even get to what we bought, a cherry on top was that I wound up selling my Elantra privately. I was all set to bite the bullet and trade it in when I guy reached out to me on CL just 3 days ago. He bought it for cash just 4 hours later, at the bank, so all was legit. It was a b-day present for his son, who was turning 18 that day. Got $1500 more for it than I would have on trade. Also sold my Miata to a true car guy...he's a racer and owns a shop specializing in FoST mods, but has a soft spot for Miatas.
On to the car we bought. I told the story in a different post, but I had let my wife test drive a '13 BMW 328i. After that, her heart was dead set on sports sedans. As awesome as the 328i is, it's a reliability gamble I wasn't quite ready to take. So we went with the one car I said I'd rule out due to premium fuel requirement....the G37. We picked up a one owner, dealer serviced since new, CPO certified '13 w/49k miles for $15k. Yeah, I gave up some of the luxuries I had set out to look for, but the G37 is one hell of a fun sports sedan...and very reliable to boot. I'll just live with the premium fuel cost because my wife loves the car. Don't have a picture of the car, but it looks exactly like this, same color....