[Twinning_N54]

So I finally starting my exhaust build for my 09 335XI, being a AWD my exhaust options have always felt limited to $1k+

I have decided to put together my own kit with 2.5" magnaflow mufflers and high flow cats for both main and secondary cats since I do live in California and have to abide by the California Air Resources Board rules.

I'm planning to get cat-less downpipes and installing Cali legal HFC right after the DP and adding the 2nd cats right before the rear axle (crazy bends)

so therein lays my question. Has anyone tried this setup? I'm thinking its going to be the best of both worlds... my concern is the length/position of the sensors.

any and all input is welcomed

thanks!