Another quick stillen exhaust review
 

Installed stillen exhaust today, and I'm extremely pleased with the results. This is my first mod with the Z so I went ahead and did dyno runs before and after.

Car put down 261 bone stock and 280 after the installation on a dynojet at Jotech in Dallas. These numbers were the average of three runs before and after the install with actual highs of 266 before and 283 after. In light of the fact that this is Dallas at around 80 degrees while raining outside I thought this to be extremely impressive.

On average I gained 19 horsepower on a bone stock 40th Z with just stillen catback and nothing else.

So far as the sound goes it's actually pretty mellow. Not as loud as I expected but it has a nice rumble under a load.

Pics to come shortly...

that seems to be the average gain for the first exhaust mod, high flow cats will net you about another 2-3, but will make the car sound much better. Glad you like the exhaust! Intakes and a tune will put you comfortably over the 300 mark.

I know that's about standard but I remained a little skeptical until I saw it first hand.

I'm glad to see such impressive dyno results. I had the Stillen exhaust installed about a month ago and my butt dyno tells me that it did increase power, but I have not had the Z dyno'd. I should expect that my increase in power is similar to yours since my car was also stock before the exhaust. I agree with your assessment of the sound as well. It's is not offensive when cruising but has a great deep sound when the RPM's climb. I am very happy with mine. Congrats on the install!

AZ