I've got an Impy, and its a lovely little (well actually, quite big) gat. Impy's are still quite upgradeable, have a full freak kit for mine, blade trigger, Voodoo derlin bolt, NDZ lightweight hammer and hammer cap.
I've been considering getting a LPR recently, to make it even more efficient and better on the balls.
Even though its old, heavy, and mine doesnt even have vision, its still great.
I've had 1 break in my last 2 cases of paint, which was only because i was running out of air. Who needs vision anyway! Tis a very good gun on the balls.
You can pick up an upped Impy from here for just the same price, if not less, as a stock Ion.
I've shot them both, and while the Ion is easier to handle, being smaller and lighter, I'm sticking with my Impy.