I would suggest identifying a mechanic with a lot of NSX experience in the area where the car is located. In some areas, there are one or two specific dealerships with a lot of NSX service experience; in others, there are one or two independent mechanics with that background.
The difference is, your average Acura dealer that doesn't have NSX expertise will look at the same things on an NSX that they look for on any other car - things like brake pad thickness, tire tread depth, etc. One with NSX expertise would know what is normal and what is not, and would (hopefully) notice NSX-specific things like a noisy aspirator fan, improperly sized tires, modifications, etc.
Usually the potential buyer pays for the PPI, but the seller makes the appointment and transports the car to and from the mechanic performing it.