Hi folks, I just purchased an 05 saab 9-5 arc with the 220hp turbo 2.3l engine and 43,000 miles. Even though it is not from the notorious sludge laden years I want to do an arx treatment as I don't know its full service history. Right now the car has amsoil 5-40 euro oil and a saab filter which the dealer changed back in July 08 when the car was put on the lot for sale. Obviously, the car sat around a while... I have put 400 miles on it in the past week. Should I just add arx and start the cycle, or should I change it out and use something else? Any suggestions for rinse phase oil? Thanks!