Porsche 911 GT3 R 2012 Technical Manual page 46

4.3.4. Exhaust manifold
4.3.5. Stop-Choc Elements
When mounting the exhaust manifold the correct nut tightening sequence
must be observed.
Porsche Motorsport emphasizes that the maximum service life for the 10
Stop-Choc elements (997.111.228.8A) in the rear silencer and pre-
silencer retainer is:
30 hours
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