Chaps,
If that's the price Ryan is looking for, then I say let him try it. He's got 400+ posts, so whilst he's not a 'Lifer, he's far from a Newbie who's come on here just to sell, therefore our loyalties should lie with him rather than a perspective forum visitor who's looking for reasons to knock his price right down.
After all, if he can achieve anywhere near the price he's looking for, surely its got to be good for all of us other Z4 owners... Let him fish for a buyer as he wants to and only when he asks for opinions on the price should everyone add their two-penneth.
Even if a perspective buyer doesn't contact him, they could be the one who's comparing his advert to yours and making yours look a bargain.
As a poster said on another thread a few weeks back, " We are our own worst enemy for driving the value of our Zeds down "
Good luck Ryan.