I just use the cheapest shit I can find, and do it every 5000ish in the WRX.
after reading up on my synthetics, i went with amsoil oil, trans fluid and diff on my c5. very pleased so far 
with the K&N gold filter, shit stays pretty clean after 4K, too…
I use the VR1 in my 951 and it runs great
Valvoline Synpower > Mobil 1
Everyone is quick to hop on the Mobil 1 circle jerk, because its omgmobilone!. There are better oils out there. Mobil 1 has actually switched to a group III synthetic recently, which is essentially a dino oil that is extremely refined to have the same properties as a full synthetic. A real synthetic is PAO (polyalphaolefin). Is there really a difference? A little, but admittedly not that much. Regardless, Valvoline Synpower outperformed Mobil 1 in a majority of the categories used to rate oils, even before Mobil 1 switched to g3.
I never understood why people would use a cheap oil in a good car. Hop onto whatever synthetic bandwagon you want, but please dont use walmart supertech in a good car. $500 beater? sure!
How is castrol syntec these days? I remember when everyone was buying the german syntec because it was superior but now you cant find it.
I’m actually using syntec right now, because pep boys had a terrible selection the last time I went, and couldnt find any synpower in the right weight. Syntec is rated close to synpower in most tests…
I had an account when i had my shop that only used mobil1 in their fleet. we had to tear an engine down at about 180,000 and i have to say thatr thing was clean as hell inside. i was impressed. but not enough to justify the cost I run shell rotella T(high zinc) in my small block (flat tappet cam) and have always noticed good oil press etc… no matter how hard i beat it. of course you really dont want to use it in something with a cat on it
omgthereisELFinmytransam