How to de-cat my 3rd gen petrol Jimny?

so, i want to remove my cat, or fit a sportier cat to my jimny (2000 model, M13A engine, single cat), as part of my exhaust "refresh" (sporty muffler, already installed, bigger tubing, custom exhaust manifold and possibly straight piped apart from the muffler)
preferrably the first option, but i know that there's a lambda/o2 sensor behind the cat that would give me some problems, any ideas/advice from someone who's done it to theirs?

I don't know what's checked in a "revisione" (MOT), but as Lambert said the safe route is to go Sport Cat. Another route is to talk to a local custom / performance exhaust manufacturer and put forward your wants. Most can make a bespoke system that will perform well and meet legal requirements. They have years of experience in the subject and you end up with a nice system usually made of of Stainless Steel, one bit that won't rust! 

I had the classic issue of the material in the catalytic converter breaking up and blocking the exhaust, so I smashed it out making it a DIY de-cat exhaust and it made precisely zero difference to the performance of the car.
 

i don't know, i might just de-cat it since my MOTs are done by trusted people that will let me go scot free in any case