Good question indeed,
One that I've been mulling over too, as I want to get a flagship car for the business
LS2 would be mentally insane, I would be willing to help you with parts/shipping for this as its a project I would love to be involved and to put in the magazines.
Cayman is a no for me, 911 all day long
370z also very appealing !!
I guess out the 3 above the LS2 would be the special one but also the biggest PITA.