Actually there was a test performed and reported on the Shopforum, before the crash, so I don't know if it was cached or not.
That individual used a topsider. Then he removed the oil pan to see how much oil remained in it. It was just a half cup or so that puddles up around the drain plug area.
If you jacked up the car with the drain plug off you can get quarter cup more out of it. But with a Topsider you can aim the suction hose down into the oil filter can and suck a little out that never gets removed with the normal drain out the pan routine.
Keep in mind that there is almost a quart of oil that stays in the oil cooler and associated hoses regardless of which method is used so it comes down to which is more convenient. Neither method assures you of 100% oil removal that isn't going to happen!
With modern cars that have under body covers its easier to suck it out, I am using a home made pump. It has a teflon pickup tube and I pump it out hot. I tend not to spill any oil at all when sucking it out.
I seem to make mistakes when I drain oil out of the pan and unfortunately I still have to do that on the 115 chassis because of the bloody filter underneath it
