Renok7: We have tested some of the Lubro Moly in the past. They are basicaly motor oil additives which are normally in sufficient quantity/proportion in a good motor oil. Some of those additives could very well have negative effects if mixed with newer oil. There are some incompatibilities between different suppliers. Too much of one thing is worst, somtime, than not enough of an other thing. They also use ''solid lubricants'' which, in some engine, can clog some small oil passages over time.
You can not compensate for new oil with ''a miracle in a plastic bottle'' nor band-aid a problem with any additive.
Zeus: yes, synthetic flows better at low temperature. But really, how many -30deg do you have in a year? 3?? 5??.
It always make me laugh (silently) when I read/hear someone saying he has out-smarted the engine manufacturer/engineers, car companies and major oil companies when they say they have found or are using a new product/grade/make which is better than what has been prescribed. Instead of saying ''I have been using product XXX for years with no problem and I have increased MPG by x%), you should say:'' I've been had by a very good marketing campain''.
Remember this guy who sold 6 ''ocean beach front properties in Nevada''