We put the STI on the dyno and did some baseline passes. The car made a respectable 244 hp and 245 lb-ft of torque to the wheels. This is about what I'd expect from a car rated at 305 hp at the crank -- I use a rule of thumb of 20% drivetrain loss for an AWD car on our dyno. Hmm...305 times 80% equals...hey, it's exactly 244! (I guess I'll keep using the 20% rule...)
Then we switched to the Stage 1 map on our Cobb AccessPort, and ran the car again. The change was dramatic: 264 hp and 289 lb-ft! That's a gain of 20 hp and a whopping 44 lb-ft of torque. We did all these pulls within about a half hour of each other.
For the record, the weather was pretty hot -- the temp at the dyno was 98 degrees F, and 25% ambient humidity. This isn't ideal turbo-car weather, but at least both sets of runs were under the same conditions. If you are interested, that SAE correction mentioned on the graph means the numbers are scaled up by 2-3% to try to normalize for the heat.
I did notice that below about 3000 RPM, the car actually LOST a little power, and I've heard some other people complaining about that on the off-the-shelf Cobb Stage 1 map. We'll be doing some additional custom tuning on the car, so stay tuned for more gains, and (I hope) recovering that lost low-end power.