The Pilot Sport 3 and 4 are IMO one of the best all round, all weather road tyre's out there at the moment. On track they are wonderful, they heat up quickly and can do a few heat cycles before they seem to go off and they kick up enough rain that you feel safe in bad conditions.
The current crop of P Zeros I have found very snappy, quite hard to keep heat in and spinny under high torque applications. They seem to have a lot less role over and therefore contact patch seems to be very fixed even at lower pressures. The Nero isn't too bad but the Corsa and the Rosso... I wouldn't be running down to the stockist any time soon.
If you what the best performing tyre currently on the market the TOYO R888 in the soft compound has to be head and shoulders above the rest. It works in the rain but I would be taking it carefully and mindful of standing water. It wears out quickly but boy o' boy they are fantastic - my Noble used to have difficulty keeping up with French hatchbacks who were running them. They have so much grip, are very forgiving and give you so much confidence.
One thing I would mention is tyre pressures. I have found that it's often more important that the tyre itself. Some tyres are more susceptible to it that others but a difference of a few PSI can really change the whole feel of a car especially if the tyre has a decent profile. In my experience people have been complaining about their tyre performance or that the car feels twitchy/sluggish and a change -/+ in PSI completely changes there opinion.
Experiment with this as it's the only way to understand what your set up and your driving style will best suit. I would argue that this is especially important with something as bespoke as a Morgan. In my aero running PZero Neros I have been using 18psi up front and 20psi on the rear to get a good balance out of mine for my style of driving which is fairly smooth but everyone will be different. I will be changing to pilot sports rather than Toyos next year as I am planning on doing a bit of touring :-)
Very interesting regarding tyre pressures, the dealers recommend 25psi for the Aero's and I thought that was low!
Do they not look a tad flat at 18psi?