Doesn't appear to impact Zed's, no DPF, no GPF (as it's port injection) no EGR, Adblue, and if you delete the cat you wouldn't get through an MOT legally anyway
90s JDM fine
But if your toy of choice is a modified BMW M2/3/4, Audi RS2/3/4 etc though, with GPF delete and you like a pop and bang...