No, race gas is not bad for your o2 sensor unless you use leaded, which is not necessary. Even then, it takes a long time to cause a problem unless you're running leaded 24/7. I still am on my factory front o2 after 3.5 years of hard racing and many miles worth of leaded 110-112 octane. With unleaded, there's no issue, plus you don't need to have pure race gas. A 50/50 mix of 93 and 104 lets you crank the boost and make another 30whp or more.
Anyway, there ar emeth kits with failsafes - you don't need some crazy engine mgmt for that, and if you're that worried, don't use meth. I used alky for over 2 years on a daily basis without a mechanical failsafe, but rather a combination of "failsafes" that helped keep things somewhat safe: non-aggressive tune, moderate boost (26psi), small nozzle (7), and late progressive spray (start @ 18 and peak at 26). I never had a problem and have since removed it in lieu of E-85, which is better than both race gas and meth.
Your stock ECU is fine. You can have as many maps as you want.