Hi all, first of all, I wanna say, great site, very informative, I look forward to sticking around for a while. Anyways, I have been running nothing but Castrol Syntec in my car, usually 0W30 in winter, and 5W50 in the summer, from the time my car has been brand new until now with 300,000 kms on it (approx 200,000 miles). Would like to get labwork done to see how it has been so far in my car. Does it cost much for the tests, maybe Castrol should volunteer to pay for me, since it would be good advertising if all is well. Also I just got a caseload of the new GC 0W30, and hope to try it out soon. Just wondering if this is really as good as they say, can you run it throughout summer as well, being it has a 30 weight, or is that not a good idea? As if it is, maybe I'll stock up and get 20 or 30 bottles of the stuff, assuming i like the results.