Occasionally, George will ask for beta testers when he is about to release a new version. I have a used JB4 but his beta test happened while I bought it, so he helped me sort out my initial Map 6. A couple of others here helped me tweak it.
Most shoot for e30, so about 4 gallons.
Since you only drive 300-500 miles a month, that's a tank to a tank and a half. If you can readily get e85, then I'd target that. A JB4 with an e30 tuned map will get you close, if not up to, a typical Stage 1. If you want to modify your car and void the...
I recommend you look for better fuel and budget for an intercooler. Even though boost season has started in New England, I'm still getting timing pull on my Map 6 (+8 peak) on the OEM IC. IAT's in the high 50's.