As much as I love how this has now spanned 6 pages, it is fair to say that everyone's position is different.
I don't think that anyone is in any disagreement that Pirelli's, Michelin, Bridgestone etc would be the Tyre of choice for us all if we were on a track. End of.
However, if your like me, and your weekly drive consists of 260 miles of motorway, with 3 miles of A roads at either end, I, personally could not justify the extra outlay.
Personally, I would rather put that money into reducing my service interval timings, but as I say, that is just a personal opinion.
Obviously, if you live on the windy roads of the Pennines or in the Scottish Highlands and you can justify that extra potential 5% of Grip, then by all means go for it.
I think what we must remember, when deciding upon Tyres in terms of safety, that you can pick up perfectly legal part worn Tyres in a variety of sizes for a matter of pence, rather than pounds, and that those Tyres will be and are used on people's Motors who live on a much, much tighter budget than what I expect an average 159 owner does.
Personally, you would be correct to argue that the Accellera tyres are not the best, highest performing Tyre available on the 19" market, no. However, I would say that though these Tyres do not offer that final 5% of performance, I, personally would argue that they are not dangerous for daily road use. If they were, they would not be legal to buy or sell.
Note: I used the word "Personally" several times in this post, as these opinions are purely personal opinions. I can not afford a Rolex, in fact I keep 3 £7 Casio's in my locker, as I have a habit of breaking them at work.