Same, 87 here but on a rare occasion I'll put premium in if it's cheap enough or if I'm going into mountain territory (high rpms going up mountains - I'm usually in 3rd or 4th trying to get up I74 in colorado, less knock).Yes, that's old school thinking. I've put cheap 87 in mine forever and it runs like new at nearly 130K miles. It seems to have a tiny bit more performance with 91/93, but since it's generally $0.50+ more per gallon it's not worth it to me.
My Custom Tune would help even moreI started running 91/93 in my car and noticed quite a large difference. I'm running a K&N CAI as my only performance mod and running 93 seemed to make it rev out a lot smoother and somewhat quieter. I get up to higher speeds without even realizing it now lol
Also, in the owner's manual of my car it says the car can run 87 but for best performance it recommends 91.