I am not aware of any issues but as I have been reading there seams to be an issue. We can't please everyone but when there are more and a few concerns then I agree there is a problem. I can tell you that one of my job descriptions is CS and QC and I can assure you I will do my best to address any of your concerns. You all have my email and I would like to hear any feedback you may have positive or negative, how else can we improve if don't hear the bad and the good.

On the E46 M3, their midpipe didn't use mandrel bent pipes and they also used some less than ideal stainless, which ended up rusting.

I addressed the mandrel bending on a previous post and again we can do it its costs more but we can if requested. As mentioned there will be surface discoloration/rust but it will not penetrate the metal. Did it rust right through or did it change color? I don't know what was used before but as mentioned the piping is 409 stainless and the mufflers are 304.