The NGK's are easier to read. From what I understand the NGK's are made out of "softer" material and they are a little more forgiving than an Autolite if you do have an issue.
I have not had any issues with the Autolites but the NGK's are definitely easier to read.
1999 Z28, 80mm Turbo 5.75 @ 124 - 8.92 @ 159 on 275' s
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