I used castrol syntec for over 30,000 miles and it NEVER gave me a problem. Don't listen to the haters. Go with what you trust. Those test with the race cars and engines told me that castrol was the best and that is what I used. BTW I changed my oil 3-5k. Lots of highway miles then 5k and if it was inbetween city and highway, i did it at 4. I'm not in a city long enough to need to change it at 3k.
I say used to use it because my car is dead and I'm getting ready to revamp my new honda. I'll be using castrol for it too.
