Hi i did this earlier on in the year i changed to Falken 452's and they improved the car no end,no tramlining and also not as crashy.What ive got as backup is two cans of Holt Tyreweld which is readily available in tesco's at £6'ish and also i've got a compressor which is a Ring RAC 600 that fits nicely next to the battery in the boot.So do it you wont regret it.
P.s i did let the insurance company know but it wasn't a problem

pps the only downside with 452's is there is not much of a lip on the tyres to protect the rims :thumbsdown: