Heh, I noticed the loop on the P&W engine as well... I just figured that I wouldn't say anything and surprise everybody with an additional update. Oh well, too late for that!
It's difficult to work on the looping, as the source recordings weren't exactly perfect... I take a lot of time and effort to clean them up, and the results are something that's miles above the original source files, as far as fidelity goes.
As for the quiet engine sounds, you should probably check your sound configuration settings in-game, because my engine sounds are just as loud as the engstart/engoff ones. I should know, because I compile them in a visual wave editor (plus, I haven't edited my sound configuration, so they're of equal volume in-game).
