I'd been bringing my 09 CGTS to the same independent shop for the last 2.5 yrs or so, and been relatively satisfied with their service and rates. I found them thru the local PCNA forum - and they're good for the most part. They even allow me to bring my own oil if I could source it cheaper.

They use my own Durametric Pro when working on my vehicle, but I noticed that they had been charging me "Research Fees" - ranging from $39 to over $100 recently. First time they charged me for it, I was explained that this has something to do with downloading the durametric software to their own computer, and the last one was attributed to researching the fault codes. Even with this extra charge, I have no doubt that they are cheaper than the dealer. For an oil change, 40k miles inspection/service, to clean MAF sensor and to clear CEL (although I provided them info about possible causes of CEL from here, my cousin & Durametric) - they charged me $560. Local dealer charge $375 for oil change alone.

Is this research fee common among independent Porsche mechanics/shops?

 

Typically, that would all be included in a diagnostic charge, which is usually a flat fee unless it's really in-depth.