Several people here have tried the Michelin Pilot Sport 3+ A/S and are quite happy with it. It isn't a full performance summer tire, it's an ultra high-performance all-season. Note that the model is the 3 plus, not just the 3. A couple people have tried the plain 3 and were not happy with it.
I and others have used the Michelin Pilot Super Sport, they're incredible tires. However, they are not available in the 245/45/R19. Mine are 255/40R20, they are also available in 245/40R20. The Pilot Sport 4 is also available in these sizes.
If you really want a max performance summer tire in a 19, see if you can get a hold of some Continental ExtremeContact DW's. They're no longer in production so they're hard to find, but they're great tires and available in 245/45R19.
You can also look at the Bridgestone Potenza S-04 Pole Position, it's also very highly rated, and available in 245/45R19.
Thanks for taking the time. That was a very helpful response. What rims did you use with the PSS 255/40R20?
I'm using the T-Sportline 20x9 turbine-style wheels. They look exactly like the Tesla turbine wheels, but are 20" vice 21".
Be aware that on 20" rims the 255/40R20 wheels will rub the wheel wells in the front when traveling in reverse and turning the steering wheel more than about 1/2 turn. It doesn't cause problems, but does make noise. If this is bothersome, use the 245/40R20.