Been a quiet off-season with the Evo in repair & no changes planned for the M3 – my new catalytic converter, however, did finally arrive – 3 months after ordering the thing. It was the second part of a 2 stage process in me removing some knock the car was seeing – part 1 was the new intercooler, which seems to have taken care of a lot of it. The 100 cell (currently have a 200 cell cat on the car) should do a marginal amount, by improving flow and reducing heat. I didn’t think it would do much, but a few on the forums have actually noted a noticeable improvement going from 200 to 100.
Will go on the car as soon as I’ve got it back – which will be very, very soon.