Well, to provide some feedback on removal of the catalytic converter and blanking off the EGR.
On cold start up, the car smokes a bit more, but, once she is warm, no smoke. The car feels as if it pulls better, and the gear changes are definitely better and more crisp.
A very interesting change is that when I come to a stop, the car no longer surges/jerks. It felt as if one of the brake discs were warped and the brakes were catching and releasing.
The exhaust has a different noise tone, but, not noisier, and I hear a slight whine when I blip the throttle. The car seems to run and coast freely and overall feels more responsive. The idling seems to have sorted itself out and although it feels as if it is idling higher, the rev counter says not. The almost imperceptible miss is also gone which is a huge plus as I was never happy about that.
I will see what effect there is on fuel consumption later.
