"The American Petroleum Institute ratings that motor oils pass. If an motor oil gets the API certification it has passed testing. In addition to API testing. Most automobile manufactures have testing certifications that are equal or more difficult to obtain. Since Supertech and other brand name oils meet these certifications they do not cause sludge. If someone comments that after 2,000 miles such and such oil caused this. They are full of crap. All of these brand name oil's perform pretty much the same in 99 percent of passenger car engines when the proper maintenance is performed on the cars. There are many resources that will help you find out about this on the web just google them."

WHO AGREES??? so there is no different from walmart's supertech synthetic over mobil 1 syn?