The truth is that run flat tyres makes the bampers work "harder" and you lose some of the comfortability of the Car.
On the other hand keeping in mind you have no spare tyres so the runflat gives you an extra security.
Nevertheless ,if you decide to fit the 19" alloy wheels runflat will make your like difficult . Even though on 17" & 18" alloy wheels runflat cause you no problem...
Well ,its up to you now..