|I would only use the exstended oil change if I was using the Amsoil duel filter set-up. Oil analiss (sp) has been around for a long time. It will tell you how much sand your K&N is passing.

I use Mobel 1 only in my WRX.

Oil change before smog check in my old troopers is Mobel 1, add Delo 10-40 there after.

Redline in diffs and transmissions.

3 90 Trooper V-6's, 5 speed, 4.3L TBI, 31" BFG AT's, Fender Flairs, Bored intake, 1.6 roller rockers, MSD Coil, Jacobs Omni ignition. Heavy duty torsion bars, Rancho 9000 Shocks CAN'T SPELL, TO OLD TO LEARN, GOD BLESS YOU IF YOU CAN.