I also wouldn’t do this - my ND has the tyre sealant kit in the boot, my Mini has something similar, and I just took my E86 Z4 off runflats, put it on standard tyres, and bought an emergency repair kit and compressor for it.
However, if you buy very good runflats then (in my opinion) it is unlikely to completely ruin the car’s characteristics but you may notice a harsher ride. I didn’t like the Bridgestone runflats that Z4s the age of mine came with, but it’s been absolutely fine on Michelin Pilot Sport 2 Zero Pressure. Now it is on Michelin Pilot Sport 4 and it does ride a little better but it is not a night and day change. My suspicion is that when people experience a huge difference between runflats and non-runflats that the comparison is between bad and worn out runflats and good, new non-runflats, which isn’t particularly fair. Of course, your mileage may vary
I’ve had two cars with run flats, they are appalling, noisy, harsh, ruin the ride, handling and reduce the grip as the side walls have hardly any flex. I also found a severe lack of grip under heavy braking, a light car will skip on the road surface.
I’ve no experience of run-flats, but tyres are part of the suspension. [some] People say they don’t like them even when they come on cars designed for them, which would be enough to put me off using them on a car that isn’t.
I carry an additional gloop kit, a tyre string kit, and a jack, all of which I added before a trip to the Italian lakes. For nails and screws, plugging is fine even though it is not a permanent repair according to the British Standard and certainly good enough IMO until you can reach a tyre shop (this is not advice, just my opinion!). If the tyre is unrepairable I would have an option to remove the wheel for me or somebody else to take it for repair if recovery was not at hand.
A standard MX-5 jack was about £20 on ebay and clamps into the space provided in the offside rear wing behind the boot lining. The odd one is sold with the T-bolt to hold it in.
Of course 3 repair options and a jack aren’t as foolproof as a proper spare, but the fact is that when it would be of most benefit (halfway up an Alp on a Sunday evening) you probably won’t have had room for it anyway.
Been there done that. If you don’t push it, go for it. They do ruin the handling but you are unlikely to feel it unless you are pushing it. And at point they are terrible.
But I’ve I did have a major split on the motorway and I acutally managed another 10miles on the tyre without ruinning the wheel.
Personally if you are that worried get a space saver. Mazda 2s one should fit and it’s cheap
No one will repair runflats if you do get a puncture anyway, as there’s no way of knowing how long it’s been driven under inflated.
I’ve had numerous cars from new with runflats fitted (no option for proper tyres) and compared with non runflats they are dreadful.
I can’t begin to imagine how bad they’d be on a lightweight car that was never designed with them in mind. Terrible is the polite version, and probably an understatement.
Make sure you look after your proper tyres, belong to a good breakdown service, and take some goo with you. The odds of getting a puncture are minuscule compared with having an ‘incident’ because runflats are so bad at everything.
Just my opinion.
ATS Euromaster will repair runflats if possible. Reference below and I have also been told this in branches. I’m not advocating for runflats (as I no longer have them), but I think it’s important that the OP gets the full picture.
Of the few people I know that tried the tyre seal to repair method, not one managed to re inflate the tyre. They also had to wait for for their recovery service to source a new tyre because tyre shops don’t repair tyres with the gloop inside. They also ended up with a non matching tyre because the original pattern wasn’t available at the time.
A tyre plugging kit is ok only for nails or screws in the treaded part of the tyre.
Only sure scenario for me is have a spare wheel, even if it’s a space saver, 15 mins to fit and your on your way again, only £18 to repair at your leisure.