Just wondering what's everyone's opinion on these oil extractor pumps, such as the one from Griot's Garage for oil change purposes? Assuming you can get to your oil filter from the top as well, this would mean you can do the whole oil change without having to get under the car. Are these things as effective at removing the oil and all dirt from the engine as the classic drain method from the bottom? What happens to the drain plug if it is left untouched for tens of thousands of miles and many years? Will it get stuck in there for good? As an added bonus, such pump could also be used to extract oil samples (for analysis) without having to drain the whole oil, assuming you can keep the environment contaminant-free.