Porsche: How important is N1 spec for tyres (tires)?

I am about to replace just the rear tyres on my 2003 Boxster S. The
OEM tyres were Yokohama 265/35 ZR18-N1. Since I am only replaccing the
rear two, my intention was to get the Yokos again. The discount places
in the UK don't seem to do these in Porsche N1 spec. The choices are
therefore to pay about £60 ($100) per tyre more, get a different brand
in N1 spec (then I will have different brands front and rear) or get
the Yokos without the N1 spec.

What is the disadvantage of the last option?

--
P

Mostly you pay more for the same quality tyre just for the Porsche approval.
Different brands front and rear are no problem for road use.
My best advice is to give Terry of TerrysTyres a ring on 020 8864 2486.
I have been buying performance tyres from him for 30 years, he gives you
good advice and always has good deals on performance tyres.
Just say Martin send you.
Regards,
Martin