I have two of the P7M13... actually Gunzik I think I might have bought one from you. I know I bought at least one HK pistol from you. Might have been the P9S now that I think about it.
In any event, these are the two:
The one on the left was NIB with the box and the whole shebang. I bought it last year for $2,250 - which may sound high but... the guy never even put it up on the EE. He just offered it around to some of the guys he knew on the board here, and even then there was at least one other suitor who was desperately trying to win the affections of that 2003 produced P7M13 - so it was either pay that much or move on.
The one on the right is one of ARMTAC Chris' shipment of 15 Belgian police guns, which arrived in January of this year. Price: $999. They pre-sold out in less than one day (back in about October of 2011). Not trying to cause waves here, but I see there is someone trying to sell what appears to be one of those guns in the EE for $1,799. Realistically... he just might get that.
I paid $1,450 for a nice shape 1989 P7M8 (see my other posts) and I paid the same (or maybe $1,500) for a totally brand new in (old school paper) box 1980 produced, non-police, non-refurb, Arlington VA-marked, P7 PSP - which is still unfired and NIB. That one realistically could have gone a bit higher if the guy posted pics in the EE, as most people see "PSP" and think "worn finish police trade-in."
I think the order of value (and interest level, and rarity) is basically: P7 PSP, P7M8, P7M13, P7M10. (Other rare ones like the P7K3... of course interest level would be sky high, but they are effectively impossible to get, in the U.S. or anywhere)
The ARMTAC ones must be as cheap as they are ever going to get these days at $999. The $2,250 I paid for and NIB with the box and everything is probably market value, maybe a little high. The value of your gun is going to be somewhere in between there, probably at the higher end of the scale. If I were selling the one you have, I would not start lower than $1,800. Somebody will buy it at that price. Hell I might buy it at that price! These things are a hideous addiction.
Of course, just got to make damn good and sure those mags say ".40S&W" on them and do not have the following three characters anywhere on them: 9, m, m.
What's the date code on that one you have there? Early 2000's?
Edit: I just looked at your EE add... well, I guess this is all academic now, as it sold for $1,800. That is a fair price. You could probably gouge some desperate schmuk for more than that, but that is a fair price. I see that it is actually a real old West German gun... which I like! It looks like an "IE" (1984) gun with Chantilly U.S. import marking. collectors of course would love to have the original mags and the box and whatnot, but as a shooter, why not? And a real hardcore collector could probably piece together the box, mags, manual, brush, etc. (It would take a lot of searching!) Nice gun!