I used it on my Mitsubishi Lancer Evolution IV and now, on my clio. Both did a great job. Lower the emission and pass MOT, even its decatted. Save fuel and much improvement on the low end torque. As your know that, the compression ratio of turbo cars are relative low, 8.8:1 vs. 11.8:1. Especially after fitting mushroom air filter and fatter exhaust, the low end torque will decrease. Once you retune the Ecotek and the low end torque come back and really save fuel and provide good throttle respond.
We should make it clear whats the main purpose of the device ? If its tuned properly ? If you hate the noise without considering the true purpose of installing this device nor considering if its properly tuned, you should not have them fitted.