How much would it cost to turbocharge my 2002 Mustang GT?

You don't turbocharge a Mustang. You supercharge it. If you can handle people laughing at you and making fun of your car, turbocharging will cost $2,000-$4,000, depending on the quality of the setup and install. (edit) Trust me, I know turbochargers. My wife and I both have turbocharged cars, and I agree that turbo is better than supercharge anyday. Maybe I'm just a purist thinking that big American muscle and turbochargers don't belong together. But, assuming it's done right, I agree that you'll get much bigger gains with the turbo dollar for dollar. And if you know so much about turbocharging/supercharging, why are you asking such an obvious question online?

1) It will be around $3k for parts ONLY, plus labor or you do it, + ecu tuning 2) Stock internals its ok up to 7-8 psi 3) "universal kits" are less than garbage, because, how do you know the flow rate and injectors? universal kits dont even know which engine will use them 4) Quality is expensive, for a "less expensive" kit you need to build your own, how? you need knowledge for that, (tons of it) You can try a car performance simulator, there you will be able to set up your mustang, and see performance effects with Turbo vs SuperCharger, and you really should change your gear ratios, because your new torque curve will be different. Try all of this online at htttp://www.nxgtrsim.com