Right now PASM is the best thing coming near to a real sport suspension system. Of course PASM is much sportier than the original Boxster setup and to my knowledge PASM equipped cars sit 10 mm lower too (at least ROW cars).
On the other hand, PASM equipped cars are difficult (if not impossible) to retrofit with a coilover kit/etc.
I think for mixed street/track driving, PASM is great. And people shouldn't forget one thing and I hope Boxster lovers won't "kill" me now: Porsche never made the Boxster for (track) racing and to my knowledge nothing has changed.
So I'm not really expecting a 20 mm/LSD option for the Boxster but maybe for the Boxster Coupe.
Can't say much about the 19'' wheels on the Boxster but I'd probably go for PASM with 18'' wheels. Unless somebody wants to have the PCCB.
Chrono sport is definetely another option I would go for on the Boxster.