I've got a 1995 Mustang 5.0 that has roughly 130,000 miles that have come from Durablend 10w-30 and synpower 10w-30 (3,500 OCI). I've been intrigued by you gentleman about the Green stuff so I picked up about 11 quarts of "Made in Germany" 02 and 04 stuff. Would there be any problem switching over to GC after running Valvoline so long? The car uses about 1/2 quart every 3,000 miles and always has. Also, this stuff is a little hard to find in Southern Illinois so I might have to switch back to synpower at sometime in the future. Would this pose a problem as well?