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			Agreed.  I have run Castrol 5w40 over the last year and notice less valve train/chain noise on startup.  No other changes or indications I am aware of.  I change oil typically 2x yr  between 3-4k miles since I have been running Time Trials.  If the oil ever darkens or gets an odor I dump it right away.
		 
				__________________2009 Cayman 2.9L PDK (with a few tweaks)
 PCA-GPX Chief Driving Instructor-Ret.
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