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Old 09-26-2012, 01:12 AM
paperplane94 paperplane94 is offline
Officially Welcomed to the 'Fest
Location: Los Angeles, CA
Join Date: Jan 2012
Posts: 933
Mein Auto: 1989 525i M20B25
I don't know why, but the general consensus is that the new metal plugs cause the M20/30 engines to have decreased performance.

Maybe its a personal preference thing, but people have complained about the new plugs as of late, and people have not complained about copper plugs for the past 30 years.
My opinion is based on the experience of others and not empirical evidence. I would imagine it to be hard to test this kind of thing, so go figure.
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