I have had run flats on 2 cars in the past, a BMW and Mini and when needed my local Indy never had an issue taking off/fitting a tyre at the normal rate. He was also able to repair a puncture in the tyres providing that the repair was in the permitted area and I confirmed that the tyre had not actually been run flat, if it had it was scrap.

So find a place that knows waht they are talking about, clearly the Toyota dealer is clueless.

With regards to fitting non runflats my BMW winter tyres were and the TPS still functioned normally. But your insurers need to be told and there may be an additional premium to pay.

And dropping to 17" wheels with the same profile and width as the 18"'s is not an option. It will lower the car, affect the handling and also affect the accuracy of the speedo. Your insurers will not permit such a mod and it will probably affect your warranty as well.

My toyota dealer is generally excellent, but useless when it comes to tyres. They told me the 1000 mile winter tyre my wife had punctured was a write off. Local (respected) tyre dealer said no problem/

I'd suggest checking the wheel and tyre options for other cars of a similar spec in the brochure for your car ... see what toyota offer / reccomend as these may well fit your car - especially if offered for your exact model. check if the brakes and body fittings in the wheel arch area are the same, you don't want to be fitting something that fouls when turning etc.

Whatever you do make sure your insurance company is aware .. you don't want to give them an excuse to avoid a claim if such event should occur (or be prosecuted for driving without insurance if cover was to be recinded)

If you convert to ordinary tyres the TPMS will give an error which is an MOT fail. It can be switched off.

Read :tinyurl.com/m5s7uly

and other threads..

Sadly the MOT regs now state that tyre pressure warning systems fitted as standard must be operational. I was an inch away from buy a new RAV4 T180 as a second car - but noticed the standard run-flats and decided against it for this reason alone. If there is a way of fitting standard wheels and tyres whilst keeping the tyre pressure warning system happy then that's certainly the way I'd go.