Worth checking if TPMS is a legal requirement with run flats, even the vehicles age would ordinarily put it outside the scope. From a day to day safety point of view might be advisable even the law doesn't require it.
First thing I did on my mini was swap to normal tyres, less noise, lighter and far better ride as @Tristan says, they are rigid walled. From a personal view if its to save money, just try and get some second hand standard ones, loads of stuff runs 15s.
My previous car had run flats as standard equipment, no choice in the matter. I can see the thinking behind them, not having to change a tyre on the side of a dangerous road etc. etc. I ran winter wheels and non-run flat tyres for half the year and the car was definitely far more comfortable (plus like for like they were much cheaper to buy). I had one puncture in the almost 5 years I had the car... be aware even it's something you'd have easily got done on a standard tyre you may struggle to get a run flat repaired. Can mean a new tyre every time All the bigger name places here wouldn't touch it, they don't know (nor do you probably) how long you've driven it below recommended pressure and caused unseen, internal damage. That's why I was thinking TPMS was mandatory with them fitted, stops you driving on as normal and oblivious to a deflating tyre.
Personally I'd worry about an unknown puncture with having no tpms. But as for ride quality and noise I have them on my daily and I cant say I've noticed any detriment to either so wouldn't rule them out on that basis.
Reading @Zender Z20 post reminded me, was only a few places that would swap the tyres due to the machine not being set up for them, was a while ago admittedly. Also my bmw had them mixed with normal tyres when got it, so ended up fitting new wheels complete with tyres within 2 days, then used one original as a spare, minimalising the already tiny boot. Did have a set of Dunlop Denovo wheels for a mini 1275gt sat behind my old garage for years, now they were something else. Metric, bolt together and mousse canisters inside a rock solid tyre.
