Exterior:
Upgraded Aero
Small Rear Wing
Interior:
New Bucket Seats (JDM STI Seats)
Different Interior Trim (Gloss black maybe)
Altered Gauge Cluster and Steering Wheel (STI Badges)
STI Push Button Start
Wheels/Brakes/Tires:
17" BBS Wheels
Better/Wider Tires (Maybe 235/45)
STI 4pot/2pot Brakes
Suspension/Chassis:
Stiffer spring rates/struts (1-1.5" overall drop is fine)
Upgraded Bushings
Upgraded Control Arms
Thicker Sway Bars
200lb+ Weight Reduction
Engine/Drivetrain:
Improved Intake Design
Improved Header and Exhuast Design
ECU Changes
Valvetrain/Headwork (rev to 8,000rpm from the get go)
Upgraded clutch and flywheel
Lightweight Driveshaft
Approx. 230-240bhp
Honestly, if you think about it, all Subaru really needs to do is make this:
Throw on all the optional STI aftermarket parts on a BRZ limited, take off some weight, improve the handling a bit, add some power and call it a day. We're probably never gonna get some sort of F/I standard with the car so instead of pouting over it, focus on something else: weight.
Go from a 200hp, 2800lb car to a 240hp, 2500lb car. Honda S2000 power in a Miata