You won't find any flat out "bolt on" turbo kits that are worth the time or money you'll put into them. If you want a turbo Mk3 Supra, then spend the cash and the money and the effort and swap out the 7M-GE for the turbocharged 7M-GTE.
Yes, you need LOTS of work to put a 2jz into one of these cars. Transmission, ECU, electrical, gearing (rear end), getting wide enough tires, the tranny is said to not fit correctly without pounding in part of the firewall (though I've heard otherwise as well), etc...
You need VERY deep pockets and lots of time.