As with most specialized automotive equipment, the best place for you can buy a 2007 Mustang V6 turbo kit is online.
Websites such as AmericanMuscle.com and TurboKits.com offer great selections of kits that are compatible with that model. Even AutoZone’s website has some for sale.
You can expect to pay between $3,000 and $4,000 for the kit, plus another few hundred if you want to have a mechanic install it for you.