Back before the Cult site went TU, I recall there was at least one person there that raved about how great "foaming bore cleaner" worked for completely cleaning the gas setup. Have no personal experience of the product: so far I've been okay w. spraying in Hoppe's or Shooters' Choice, letting it marinate a few minutes and giving it a thorough brushing (both PSPs had a brush in the box and I'm using one of those on the M13, too), so the usual disclaimers, YMMV, etc.
As for the P7M13, I don't think we'll ever see them generally priced at what anyone that works for a living would consider "reasonable". Unless one stumbles over somebody getting rid of theirs that's completely unaware of what they've got and/or what the current going rates are. In my case, after deciding I
really,
really, REALLY wanted one, just bit the bullet, found one for sale with finish and sights I wanted and sold enough other guns to put the money back in savings after the fact... Cleaning out almost all of the combat Tupperware cluttering up the place pretty much did the trick there. And made deciding what to carry any given day a lot easier.