seeriously jon, dont be scarred. bmw m3's and porsche 911's have slight stretch straight from the factory, just like your car.
you know sometimes you go to you your car and a tyre looks a little low on pressure and you think to yourself "it'll be alright, i'll stick some in tomorrow..."
well instead of that you need to think, "that tyre looks soft, i better put aur in it!
your tyres will only off if you go flying round a corner with 15 psi in.
stop panicking!!