STi:
Brembo brakes, suspension, BBS wheels, EJ25 (motor), catless up pipe, cat back, 6 speed, DCCD, rear wing, hood scoop, water sprayer, STi I/C, HID's, fog covers, side spliters, side skirts, seats, steering wheel, radio, carpet, inner door panels, no sound deadning, no trunk pass through, no optional moon/sun roof, gague cluster, 4.9 0-60 13.2 1/4 mile.
WRX:
Radio, small/no rear spoiler, fogs, EJ20 (motor), 5 speed, more cumfortable ride, better gas mileage, 5.4 0-60 low-mid 14 1/4 mile.

Nick

 

That 0-60 for the STi sounds a bit high. But yeah, those are the differences. Go to the dealer, sit in them, get the brochoures and you'll see the differences.

 

I have driven both (own a wrx). The STi feels fast even fully loaded with passengers and luggages. Can't say the same for the wrx. The STi transmission also feels crisper than my wrx with the factory short-throw, and the 6-speed generally feels more bulletproof. At 1500rpm with the higher displacement engine, there's enough oomph to accelerate at a decent pace if you are too lazy to downshift; on the 2.0, it would struggle until slowly reaching 2000rpm.

That said, even after going and coming back from driver's paradise (STi), my minorly modded '03 wrx is still a blast to drive. But realistically if I were in the market to buy a car now, STi would be a no brainer since I can afford more insurance payment now.

 

If you can afford the STi then get one, you won't regret it.