I used that stuff the last time I did an oil change in my crossfire. There was no problems with the engine before and there is no problems with it now so I never noticed a difference in anything. However, I had a '99 F150 with high km on it and once and a while when I started the truck it puffed a bit of smoke. I added the lucas oil and it stoped. I was not using synthetic or anything special but it stoped the smoking.