what year car do you have? most mustangs have a 6250 rev limiter. If your scared say your scared? a 75 shot dont seem like its a 200 shot to me. I would practice shifting off the bottle to save your nitrous too. So you dont have to fill your bottle every other day. Then if your sucessful without breaking your transmission off the bottle, hopefully you have a short throw shifter. Then take it out and mash your foot to the floor if your nitrous is set up to activate off a full throttle switch it will only be spraying your Nos when your foots at full thottle, but expect the tires to break loose most likely spraying the 75 shot on while powershifting. Dont be scared. Get good at shifting without it so your better when you spray it. Wear a helmet. Fire retardant suit etc. Maybe get a rollcage and a driveshaft safety loop. Dont want your car catapulting down the track it the yoke snaps on the
tranny. But i dont think a 75 shot would feel really deathly fast. Compared to say a supercharger adding 80+ hp to what you already have. So just go run it, rip the stick out of it. See what it does. Till it blows up tear it down then rebuild it hopefully you dont lean out and melt a piston or break a rod. Good luck.