Will be picking up a new 08 Subaru STI shortly. Subaru now recommends (requires?) a 3750 OCI. Keeping to that schedule would seem to mean synthetics less necessary (or would it? what about coking etc.?). STI owners, what do you do? Keep to that schedule with dino? blend? Ignore it and go with syn? Favorite brands? I used GC in my now sold Forester XT to good effect, but not sure I should stick with it given this short OCI requirement. Thanks...