I noticed that almost all posts on exhaust sytems and ECU upgrades had the ECU modified and then the exhaust done. I recently had a Milltek full exhaust (headers & cat back) and
EVO intake done at ICS Performance in Stamford, CT (
www.icsperformance.com).
I was looking for an increase in performance but did not want a major increase in sound level during routine driving. The Milltek system, if anything, seems quieter during routine daily driving (lower pitch (lower hz)) than stock, but has an agressive sound when the rpm are above 4,500.
The pre-exhaust dyno (dynojet) showed 261/229 hp and torque respectively. This works out to about an 11.5% loss at the rear wheels compared to the reported stock 295 hp at the flywheel. After the full exhaust and intack the dyno showed 284 / 244 or a jump of 23 hp and 15 ft.lbs. This was right in the upper range that most people were reporting 20-25 with the better exhausts (and which I was skeptical about). (SEE IMAGE)
The Milltek shows excellent workmanship and the headers/cat back blend well with the car (SEE IMAGE FROM BELOW). There is a respectable increase in performance and the sound is agressive when you want it to be but very liveable day in and day out.
After the install and testing, we then did a GIAC ECU upgrade and did not notice any change in the dyno numbers. This was after multiple runs, fans blowing into the intacke, etc. After a number of days and no change, the original programming was returned. The change of 23 hp / 15 ft lbs seems as good as most are getting with the ECU/exhaust/intake. Why we did not get any change with the ECU modication is not known, except that ECU modes in a normally aspirated car running stock premium fuels is usually very limited.
For any one looking for a reasonable increase in prerformance without any bothersome drone during normal driving the Milltek seems like a excellent choice.