I've used Golden Spectro (semi-syn.) protects real well, runs dirty, spooges alot, approx. $4.75 for 12oz. Champion WP2 (semi-syn) cleanest burning semi-syn. I've seen, protects real well, spooges less than Spectro, approx. $4.25 for 16 oz. Red Line (syn.) very clean burning, good protection, minimal spooge, $8 for 16 oz. ! Mobil 1 MX2T (syn.) burns very clean, good protection, the least spooge I've ever seen, $3.49 for 16 oz. available at Auto Zone ! Amsoil Series 2000 (syn.) burns very clean, good protection, minimal spooge, approx. $8.25 for 32 oz.
All are cheaper by the gallon !