Grip, yes - blowout, no. I think we're arguing the toss over similar arguements
Effectively you want all your tyres to be matched, and with good tread. Fronts do most of the work, therefore need to be in good nick. If you want to avoid a tyre failure-related visit into the scenary then good rear tyres are more important.
The way to control a front tyre blowout is to bleed speed off gradually - clearly if you're cornering at the time it won't make any difference as you won't have time/space to do anything about it. If a rear tyre goes you're really a passenger and can't control it since you don't have any single factor (eg steering, braking, throttle) that you can use to bring it under control without more than likely making the loss of control worse - it might behave, or it might not depending on failure mode of the tyre.
I used to work as a primary safety (accident avoidance) engineer & test driver so my opinion is based on trying the different options out.....
In the Cupra R's favour is the fact the wheel's are 18" diameter so even if the tyre disintigrates you've still got the rim to drive on until that breaks so you're unlikely to get the opposite corner wheel lifting. It's an emotive subject and everyone's entitled to their preference.
