When my RS was still stock it felt like I was always towing some heavy invisible cargo when I want to accelerate hard from 80-120km/h even if its just only me in the car. For stock low end power it was adequate and responsive, but when climbing hills its not very fun at all.
After I got just the CAI the car loves to pull to redline after 3500RPM but low end power was still an issue. The response starting from a cruising 80km/h to flooring it to 120km/h was quicker but still felt there was a bottleneck choking the airflow.
Finally got the headers & catback installed both at the same time. First noticeable difference; IT IS LOUD AND DEEP! It sounds agressive just like an SVT Cobra, and got the low rumble at idle. Incredible power is felt throughout the whole RPM band, pushing the accelerator a little can easily jump to 4000RPM so now I can down-shift with much more ease.
Going from 0-100km/h is fast! and from 80-120km/h I don't need to down-shift to 3rd and I can still pull strong with 4th all the way! The combination of the headers, hi-flow cat, and Tanabe RM cat-back is good money spent for the power.
The whole setup is quite loud, but at cruising its quiet like stock. Only when accelerating or WOT that there is a loud deep tone. No need to worry about cops cuz the sound isn't intrusive or get too much attention unless you rev at him.
An added spice to this is the popping I get when accelerating after I let off the gas. At first I was kinda worried, but this is normal everyone says. My friend who drives an FC said its hard to get those popping noise for cars with piston engines, which he always say that is exclusive to rotary engines. All this just makes the whole setup more agressive and intimidating! HaAaAW!
I'm very statisfied with the new-found power. Though only minor problem is the bright CE light that is flashing in my eyes now. Its no biggie, the guys at Brullen are gonna fix that for me next week since they promised no CE light. I like how some people nowadays still keep their words true; the people at Brullen are excellent!