Here's a little update on the experience with the Cargraphic sport exhaust for the 997 Turbo (200 cell cats, OBD2 compliant, TÜV "sound version"):

1. the first couple of kms were pretty disappointing, the sound was too "low", it also created some vibrations in the interior, causing some interior noises.

2. exhaust seems to work perfect, no engine warning light coming on and I just checked the motronic after over 800 km with the exhaust with the PiWiS and there are no problems saved, nothing...so it really seems to be engineered very well.

3. apparently power/torque has increased in a certain rev range, I saw 1.0 bar boost pressure much more frequently than before when fully accelerating, usually I get 0.9 to 1.0 bar. So it is possible that the 21 HP power gain claim and 20 Nm torque gain claim may be accurate but ONLY in a certain rev range, so don't add it to the maximum power/torque figure.

4. for the 997 Turbo TIP, this exhaust seems to add a slightly better acceleration response when starting from standstill, this is really one of the improvements I felt immediately. Apparently there is much more torque available slightly over the idle rev figure.

5. finally, the exhaust got louder and "clear/crispier" in sound, the low tone didn't disappear completely but it is much better now and even at very low rev figures, the exhaust started to sound nice. Interesting enough is the fact, that the exhaust sounds MUCH nicer from the outside than from the inside, bear this in mind when you own one (let your mechanic or a friend drive your car on a parking lot and you'll realize immediately what I mean).

6. at rev figures above 4000 rpm, the exhaust sounds like a racing exhaust, very loud with a high pitch tone and also interesting: you hear "sucking" and "blowing off" sounds all the time, apparently Porsche tried to "cover" these sounds with their OEM exhaust. These sounds may annoy some people, personally I just LOVE them, they remind me of "classic" Turbo cars.

Two days ago, when it was pretty cold over here (only 2*C), I encountered two times some sort of "stuttering" at almost the maximum rev figure with a pretty high boost pressure (1.1 bar at over 6000 rpm). First I thought that this may be a problem caused by the exhaust, later on I may have figured out that the PSM was actually coming on...in SECOND gear. Ouch. Not 100% sure about this, we're looking into it but since the PiWiS didn't show any problems, I suppose the AWD setup on the 997 Turbo isn't really 100% fool proof.

The street was dry and no, no ice/frost yet (temp. at night weren't below 0*C).