www.blackstonelabs.com
At your next oil change, take a sample from "mid stream" and send it in.  They'll tell you exactly what shape the overall oil is in and can make milage replacement recommendations based on actual (gasp) science.  They can also tell you what else is in your oil that shouldn't be.
It's about $20, and they send you the collection kit & pre-paid mailing kit for free.
			
				
			
		
 
		
		
		
			
		
		
		
		
		
			
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				A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608
 
Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.
