I think Amsoil is quite a step above Royal Purple. I also have a 1999 SAAB 9-5 that was suffering from the dreaded "blue smoke" condition. I switched to Amsoil products, and used the engine/transmission flush before the first oil change to their Signature oil. After one treatment, the blue smoke stopped, and I felt a positive difference in performance. I have continued to use Amsoil in my Saab and Yukon, as well as my wife's Honda CRV with great results.