What you need to do is grab a wide band if you dont have one already. Just watch your a/f when on the spray. I would be more worried about a soleniod sticking open or the fuel soleniod failing before I would about the switch. If you dont have a wide band, grab one of IPS aem wide bands, the switch, and then go spray the guts out of that car. And since it is just a 100 shot, if it were some how not to work, I highly doubt it wouldnt, but lets say it didnt, and you see your car goin lean on the wide band just get out of it, a 100 shot isnt goin to hurt your car, even at stock timing.