If I'm looking for max performance a busy Shell station is where I'll go. I go through 2 tanks a week though, mostly cruising on the freeway (long commute), so I go wherever the 93 octane is cheapest close to me. Usually I end up at Sams club or H-E-B (Texas grocery chain). Both of those stations are a good 10 to 15 cents cheaper than other gas stations. Both also sell a ton of gas, so odds are the 93 is fresher than some of the other places close to me. I've had good luck with Costco 93 octane as well, but they don't take my rewards credit cards, and I don't get those sweet sweet points.
What's the deal with mixing E85 in? HEB close to me has E85 under 3 bucks a gallon. I'm just glad I can get 93 in my area, back in Phoenix 91 was the best we could get and during the summer I had to mix in some 100 octane or some Torco into each tank, or turn the boost down.
