The only main difference between the NA and TT blocks are the position of the oil squirters. other then that you can buy stage 1 TT heads from z1motorsports and build up the rest of the stuff. Im almost finished with my TT swap it took me 5 months so far. But im doing alot more then just the TT swap. I put new subframe bushings on, Diff. bushings, rear upper control arms, rear toe arms, TT motor, UR underdrive crank pully, Areomotive FPR, Z1 1pc drive shaft, Mines ECU, Noltec Urethane motor mounts, Nismo tranny mount, Braided SS brake lines, SS clutch line, EGR removal kit, New Main engine harness, Exhaust wrap, and a front mount IC. If I were you I would buy the 2+2 Z then swap a TT motor in I spent about 2400 on mine. getting a uncut harness isnt that big of a deal, they cost 350 then all of the little odd and ends youll need you spend around 5 or 6 K in parts plus the price of the 2+2. or you could just buy a front clip for around 33 or 3400 shipped. good luck with what ever your friend decides.
i heard bad things about the mines ECU.go with a jwt or ash spec.mince will lean the car out way to much.and if u can go with some good side mount intercoolers.if i knew better when i first bought the car i would have.unless u have a upgraded rad ur gonna have overheating issues