Many years ago, just before my second MOT, I had to replace my exhaust or fail mot, the flexi had failed and one of the silencers had a hole, the exhaust was a standard mild steel, I elected to have Powerflow in Aylesbury custom manufacture and fit a stainless system which was cheaper than a new mild steel one from Toyota or a factors.
This was before I joined this wonderful forum otherwise I probably would have gone a different route, Powerflow in the UK is not as good as Powerflow is in RSA.
I would still have gone custom stainless over mild steel if only because of the longevity factor.