Hi SlickGT1 - You can get a PPI done at any BMW dealership, this is how i did it.

1. Lurked around here for 3-4 months trying to read as much as I could and understanding what features i needed.
2. Went to a dealership and drove 3.0,4.4,4.8is (took me a while to get a dealer with 4.8is)
3. All this time i was looking at pvt party listings as well, once i found the one i wanted test drove it and agreed on a price...subject to the condition that i'll buy only if PPI came out good or previous owner fixes all issues or reduces price...PPI came up with stuff that needed to be replaced, hoses mostly and control arm bushing, which previous owner was ok to pay for....I knew going that i would loose the PPI money if it came out with a lot of issues and i did not want to buy it :-( (around $180)

In my case...Dealership prices for a good 4.8is were pretty high and I usually buy cars from pvt party.