I would really like to order one of these, but there is one thing that I am worried about. Maybe you guys can answer this for me. Won't a good deal of oil remain in the pan after it is all drained out of the valve? Maybe you could jack up the back, but it seems to me that some will still remain in the pan due to the shape of the valve.

 

I have one and I think the amount would be negligible, The wall thickness on the valve is not enough to make much of a difference,
Ricks is now selling them at a good price and actually I don't think it could affect your oil change as much as say draining the car on an uneven surface, If you are worried about it you can always drive your drivers side wheel up on a 2x4 before draining the pan!