Actually, for speaker cables it all depend on the gauge. The quality in that arena would depend mainly on the anti-corrosion characteristics. So with that said, a 14 or 12 AWG at 75 cents / foot would sound equally as good as the $40/ft cable from MC or even Cardas. When I was killing time on that subject, I've also read a scientifc and blind test report on that subject as well.
Sorry to say, but it's mainly pyschological rather than actual.
But back to the subject oil subject at hand: If everyone gather around the right side of our 'busas to read the little sticker, it just say 10-40w SG classified/approved. Nothing in there about using specifically "motorcycle" oil only.
With that said, I'm wondering if they're still running the $1.99 special at Kragen for the Valvoline and Castrol synthetic blend (regular auto)?? I'll ride down there to check tomorrow.