Question 1: "He was out almost before his little green Toyota had stopped" == This sentence uses an exaggeration to put emphasis on how he got out of the car, and it means that he got out of the car so quickly and purposefully, that immediately when the car was stopped he got out. Emphasizing that it was so immediately that it was almost as if he got out of the car before it stopped. You could say the same thing with "He was out as his little green Toyota had just barely stopped" but that doesn't emphasize his exit as well as the original. The sentence you added "He was out before his little green Toyota had ALMOST stopped" would mean that he was out of the car before he tried to stop his car, but the car didn't stop. So, in that case, the car is still going, because something didn't allow it to stop. Question 2: : 'He had been out almost before his little green Toyota stopped' does not appear grammatical to a native English speaker (AKA whether or not the sentence uses correct grammar, it isn't something someone would natural say, and I had to read it a few times to figure out what is meant). "He had been out" is telling me that he was out before, but he is not now (either he is back in, or he is somewhere else), or that he is in the state of being "out" and has been for some time now, which loses the meaning of him exiting the car. Neither of these really fits with the fact that his little green toyota stopped (just now). "almost before" is a confusing phrase here, I think in the original sentence, the word "almost" means "it happened right as or immediately after the car stopped" and because "been" implies that the action continued over some time, it doesn't completely make sense.