PPI.
I had 2 boxsters PPI'd at Hergesheimer Motorsports in Lake Forest (OC)
www.herg.net
I paid about $180 per car I think......they did all the regular stuff and checked the Compression dadadada plus pointed out that one car had the RMS recently replaced and was currently leaking (the one I didn't buy).
It was definitely worth the cost.
KRZ