Oil filter AMSOIL or OEM Mazda

Using Amsoil 10-40 and an Amsoil filter, Blackstone said the oil looked clean and ready to keep going at 5.5k miles. Changed the filter and added a quart to replace what was lost to the test and filter change, and kept running it. They were still happy with the results that came at 10k miles. This test was on a a 93 octane APR 1.8T that's run hard constantly.

I prefer Amsoil and their filter...I drive about 187 miles per day when training and the right oil makes all the difference. I tried Mobile 1 the first time but think Amsoil works better.