I'm looking at buying an 88 Turbocoupe and have some ideas on what to do for some performance.

Big Front-mount Intercooler
Mustang 5.0 Throttle body
Ported Stock Intake Elbow
Tial External Wategate
Stock Turbo with 25+ psi
Stock 7.5 Rear w/Mini Spool
4.10 Gears
15x8" Weld Draglite wheels mounted on Hoosier 26x9" Slicks

What 1/4 mile times are possible with this car.

 

I hate to be the bearer of bad tidings, but...................................
A big FMIC is nice but pretty hard to adapt to an '88 TC front end. Stinger makes an awesome piece. Might want to consider that one.
Forget the 5.0 throttle body. All it really does is make the throttle sensitive. Really doesn't come into play unless the motor is built all out.
Ported upper and lowers are nice. Check out 40bob.
No need for the Tial external.
The stock IHI peaks at about 18 psi. Upgrade to a T3 or Holset.
The '88 comes stock with an 8.8 rear. 3:55's w/5 spd and 3:73's w/auto.

You'd be better off running a 3" exhaust system and concentrating on head work. The air in/air out systems are the restrictions on these motors.