Conventional NO2 wisdom dictates that a shot of up to 1/2 of the engines normal hp potential is safe. It follows that an 03 Cobra rated at 390 hp (for arguments sake we'll round up to 400 to make the math easier) will "safely" take a 200 shot...just don't blame me if you blow your engine! I would NEVER run that shit in my car!
I'll never spray more than a 50 shot. I'm not a big fan of multiple power adders. I used to spray 150 all day long on my old LS1 with no problems. I think the blower introduces too many variables for a big shot.