I've had Porsche Warranty couple of times and Warranty Direct couple of times as well as dealer back to base and they've all dealt with the various problems that arose no issues. The 991 and 986 (too old anyway) I have now are not covered, the 991 had a Porsche Warranty until recently, first Porsche I've had that has not made use of its warranty and I don't plan to put one on it.
If I were I'd go to Warranty Direct and not just because they are not so picky about minor mods like non-Porsche batteries and exhausts. They covered my 997.1 and 997.2, they were willing to negotiate, not only the premium (20% less than Porsche) but also their cover so that it was more like having a Porsche Warranty (things like excess, their right to specifiy non-OE parts for repair, labour rate caps and contribution to new parts were removed).
I found their wear and tear cover to be better than Porsche in that when my 997.2 needed new rear shocks, Porsche wouldn't have usually covered that, but WD did. On the other hand, when it needed a new PSE silencer it was under Porsche warranty and they used their discretion to cover it, I doubt WD would have done that, same with the illuminated kick plates not illuminating.
Over the two 997s, WD paid out for shocks, other suspension parts, steering rack, water pump, tandem pump, plus things I may have have forgotten and they did so without fuss. Centre Gravity did the suspension work and OPC did the mechanicals.
I haven't had a WD policy for a couple of cars/years, but I did get a quote for the 991 and noticed they've restructured their products so for all I know they aren't as flexible nowadays, but in my experience, as long as you take the time to understand their products, request changes if needed and use them to the letter of their t&cs, they're very good.