Eaaaaasy grasshopper. You're in over your head and you haven't even picked up a wrench yet. What you propose is the equivalent to taking your first boxing lesson, then expecting to be able to fight like Mike Tyson in his prime, your first time in the ring.
You've not at all stated the budget you've got to work with, or your intentions (daily driver, weekend cruiser, drag strip, autocross, etc) nor have you given any other real details about the car. I suggest you spend several hours....if not weeks searching through threads around here and other forums to see the amount of time, work and money a project like this is going to set you back and re-asses.
If I may be blunt....
I'm going to take a shot in the dark here and guess that you're in your early-20's, at the very most. You've probably got a lot of car buddies....most of which are into the imports scene and give you a lot of
for owning a Mustang. They live their lives like a Fast and Furious movie and after multiple Sunday night trips to the local Costco parking lot, these guys have probably got you convinced that in order to even hang with their fart cannon, shopping cart wing sporting imports that you'll need no less than 500hp not to be completely embarrassed and at least 600hp to remain somewhat competitive.
The sad truth, is that you and your buddies probably watch too many Youtube videos. It's a safe bet than no three of their cars put together is even making 500-600rwhp, no matter what they've told you. Not one of them has ever been out of the 15-second zone, even though they all know and guy, who knows a guy that runs 10's with the same set up as theirs.
Here's what you need to know. A 500hp SN95 Mustang will run well into the 10's. A 600hp will be knocking on the 9-second door. You'll need to swap out 90% of the parts of the production engine (including the block itself) in order to sustain and make those power levels.....but the fun doesn't stop there. Unless you only plan on having this car live one or two passes, you'll need to swap out the transmission, upgrade the fuel and ignition systems, rear end and go over the chassis and
suspension from one end to the other just to keep the car together. Plan on spending at least $25K, if not more on top of what ever you paid for the car (and even then that's only if you get a deal on the parts and labour) and at least a year of your life trying to make it happen.
Above all else....remember this saying.
FAST, CHEAP, RELIABLE......Pick Two!