Just my two cents on oil...
Oil is used in a engine for lubration purposes(duh

)and to help cool the engine. The job of an Oil Filter of course is to filter out any media that might get into the oil, before it fowls up interal compents like your oil pump, etc.
Normally Your Oil Filter is just about useless after a couple hundred miles since the filter media inside of it gets cloged up by little shavings etc in it, that where inside your oil.
Synthic oil is usally normally better then your typical Dino type Oil. Its best suited for applications that have a high heat load like on gas turbine engines or in situtations on where the changing the oil isnt all that practical do to localation etc..
As for oil changes....well I like the 3K oil change theory myself...doing oil changes every 3K is cheap insurance for the heath of your engine, esp if you do it yourself. How can you go wrong for $10 bucks an oil change if you can do it yourself?
I run synthics in my Mustang now....$30 dollars an oil change is a bit much but I have piece of mind that its done right and I don't have to sweat it too much if I go over a 1K or 2 over that 3K mile limit if you will call that.
Just my two cents on the subject matter....
Scott
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1998 Mustang GT for now..
Mods:
K&N
Pro 5.0 Shifter
Steeda Tri-axe shifter handle
White Gauge Faces
Koieng Villains with 255/45/17s