Most of the turbo options out there for the Z require custom piping unless you can get your hands on a top secret Greddy turbo kit. I personally would go for the Sprintex as it is a complete bolt on kit and can be easily reversed if selling the car. As for mileage 60k miles is not much for any Honda or Toyota out there. There was even a Toyota Tacoma that had 1,000,000 miles on the ODO. I would not be surprised if you could push the Z to 300k miles well maintained. The Z has good gas mileage and is fun to drive.
2011 CPB CRZ
Suspension work, intake, exhaust/2nd decat
2017 Black EcoBoost Mustang
Suspension work, Bolt-ons, BAMA tune