Whatever you may do, don,t do what's described as a run-rite system service by Pep Boys. Its the reason I'm the owner of my first MK8 now. The service consist of disabling the the fuel pump, tying a bottle of mystery fluid into the intake vacuum port. Starting fluid is used to restart engine while FP remains disabled, the engine is then fed through an IV like setup the mystery fluid, on a constant slow flow introduced into the intake through a vacuum pull, is what the engine is now running on. Cleaning the system while running, it may run for upto 40 minutes. The problem exist because this fluid raises the engine temperature to such an un-healthy degree that major stress may occur as a result. Especially if your vehicle is a high mileage one.I had a 96 Mercury Sable that I wanted the service performed on. As an experiment mostly. I was an employee at the time. We did a reading of engine vacuum it read between 16 and 17 inches of mercury before the test, after the service an increase of almost 20 inches of mercury. It cleaned the innerds real well but the stress factor of the cleaning within 2 weeks completely destroyed the engine. Causing a main journal bearing to be thrown. It was like nothing I'd ever experienced before. After doing about 90 MPH on the expressway, I saw the oil light do a constant and the check engine light which had been on perpetually begin to flash off and on consistently. Searching for any evidence of oil leakage I found none. There had been major internal damage only to be rectified by replacing the engine,which has yet to be handled.
Borg/Warner has a treatment that runs through the fuel system, I know because it was PBY's competition and during our training session they tried to get us to see the benifit of theirs over B&W's. These services are done by PBY's staff exclusively and some (mechanics) who are in a hurry who rush to grab another job often do the service improperly anyway by not allowing a slow but fast process, causing a hellacious smokescreen emit out of your tailpipe and the smell arrghhh...