Bummer.

Can't speak for US owners, but in here in Canada that's not the case.

With performance tires being short-supplied, do UK dealers expect you to park your car and collect dust in the event you are unable to source proper N rated in TT/S sizing?

 

Warranty on what? The whole car? They can't tell you what tires you have to run in order to still cover the engine etc under warranty. Yes if they could prove that some issue you had was a direct result of the tires they could deny that claim. But this holds true for any mod. If you get an aftermarket exhaust that doesn't void your entire warranty on the engine and drive train etc.

 

In the US, this is generally correct. It has to do with a law (Magnuson-Moss Warranty Act) that sought to protect consumers. However, other countries are free to legislate / litigate as they see fit, so your rationale is not necessarily correct in the UK.

 

Yes must be definitely different over there as here to apply for an extended warranty (Porsche changed the rules so cars upto 15 years old and 100,000 miles max can apply for it) need to go through a 111 point health check

They check stuff like:

Rev ranges
Must have an original Porsche battery
N Rated tyres
Standard exhaust
Standard suspension
Full service history

If it fails the 111 point check you need to rectify the work first

So not as straight forward here i guess

 

I could be wrong but I would contend:

Because a Porsche dealer must have their used car wearing N Rated tires (or Tyres ) in order to qualify for Porsche's extended warranty program, does not mean that car must remain wearing N Rated moving forward once they have worn out, to maintain full coverage as outlined within the extended warranty program.

I've changed exhausts, tires, rotors, brake pads and even wheels to off brands and still maintained both the original warranty and in other instances the extended warranty with my Porsche dealer.