I feel like full length longtubes are just excessive if you want to go turbo. Turbo headers are more efficient the less piping you have before the turbine. I haven't turbo'd a car, but you're going to need a blowoff valve, wastegate, and the necessary electronic controls for them, piping for the downpipe, intercooler, etc. A kit, at least for the exhaust side, will save you a lot of time.
Edit: If your fuel system uses the same injectors as the GT, they probably need to go. GT injectors run something like 90% duty cycle with the stock tune