Give it up.

When not restricted for USA cheapskate tire buyers, you car would be a 150mph autobahn burner. Can't do that with "restricted" exhaust.

BTW, "restricted" exhaust is a concept that exists only in the minds of advertising copy writers.

Save your money for maintenance.

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles