Say I really wanted to clean my engine. I am using PP and MMO right now. After running a carfax I see that my car used to be a rental car and now I really want to clean it out slowly without ARX. I would like to use a good HDEO and MMO to maximize cleaning. What is a good 5w-30 HDEO? Shell Rotella? This is for a 2003 IS300 with 115k.