I don't think ptk has been making kits for a long time.PTK Complete Street Turbo Kit: 99-02 Ford Mustang w/3.8L V-6 (3core air/air intercooled)
Do the turbo first.
I'm probablly going to make a few sets of turbo headers here pretty soon with a standard t4/t3 flange with crossover for a single setup.