Pepboys has full syn m1 and castrol syntec on sale. They come with a filter good for something other than Porsche. Cost about $5/ qt. Do not know what grades yet but I will tomorrow.
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97 Boxster 115k miles
3 spoke wheel,
OZ Racing Rims
I got the Castrol Synth full syn 10W 40. They are selling them in qt bottles. The M1 is in a gallon bottle. It looked like there was a wide variety of weights in both brands.
__________________
97 Boxster 115k miles
3 spoke wheel,
OZ Racing Rims