Wouldn't it be nice if those tyre review sites told you which model of the tyre they were testing - there are two different models of the tyre with different side walls - get it wrong and you have spent a lot of money to get something you were not expecting.
I still cannot decide whether to live with overpressure on the soft walls or go for the XL and hope it doesn't become a bone shaker.
No way i would fit anything but a reinforced tyre,
with reference to what you ask,
overpressure on the sidewalls of a non reinforced tyre would ( although a small percentage ) would increase the possibility of a blowout.
Secondly - if you DID have a blowout, i would rather have it on a tyre with a stronger sidewall as it would decrease the likelyhood of the tyre completelly disintegrating.
I like yourself thought i was going to get a rough ride when i fitted my asym 2 xl (18s) but it was no diff to the miches i had on before which where not xl's.
Also when i changed my summers for 16 inch vredistein snow tyres which are not xl obviouslly i though ah well at least the ride will be softer for the next few months - nope,,, i would actually say it got bumpier
From a safety point of view the xl would be the safer tyre but etto