The guys summed it up really well, now we could have this thread go on forever if we started discussing which oil is best, and which filter is best. My advice is make sure that you see 100% synthetic on the oil whatever brand you buy. There is a type of Mobil 1 that is not 100% synthetic, it just says synthetic on the jug, it only has to be 30% synthetic for them to be able call it synthetic, but if it says 100% it has to be. I do not like the AC/Delco filter is is made in China and it does not spin like the Bosch or K& N do, they are made in Germany, very different filter, do to the fact the oil on our filters enters from the side instead of the bottom like a typical filter it needs to be able to spin or it will get a flat spot where the oil comes in. The only AC/Delco that has ever been in either my NA or GXP were from the factory both had a flat spot when I changed them, they are also much softer than the Bosch or K&N which are kind of a honeycomb material but a pain in the but to find. Of course I am a bit anal about my oil filters and I pay $14.95 a quart for oil because I run my car out to the 7200 rpm redline quite often. I figure if I am going to beat on it I should make an effort to protect it.