I´ve a Bmw M3 E36 3.0cc, and bought the headers of supersprint ref: 784301 and the resonant substitute of the catalyst with ref: 784302 and I have a eisenmann mufller . What it is certain is that since that the collectors and the resonant had been mounted in it, the car never more was the same, was to choke in low and average rotation, so I decided to take off chip modified that it had and put the origin chip and go for the Bmw concessionaire which accused the 2 deteriorated sounding leads mufller lambdas.
Then bought 2 new sounding leads lambdas (of the mark), and the origin ECU chip, the car seems that it accused to be all good in diagnostic machine.... brought the car for house and the car continues to choke itself the car only goes normaly in full trothle.... I made already 800km with it and it seems that the car if to very walk to more speed up or in higway the speeds raised it starts to stabilize and is with decreases since that if speeds up gradually (thing that before it was enough to speed up half pedal and it walked the proportional thing soon that now it rolls and does not only walk if will be full trothle).
Another thing that I notice is in being in one 2ª or 3ª speed and to keep the foot the 1/2 of accelerator and the car goes chokeing and later when it goes up there of rotation for 3500/4000rpm starts to want to walk and it orders chokeed
and after the chokeed it orders the due one strain to be to pull the such 1/2 of accelerator. Basically the car goes well full trothle or with very low trothle.
Before changing to the headers and catalityc system the car was normal.