I picked up a S&W 3000 (Howa) with the folding stock for $99 today at the LGS.  I'm looking to make this a little project gun.  I know aftermarket is pretty scarce for this gun, but does anyone know of any manufacturers that still make aftermarket parts for them?  I have leftover stock from my Interstate arm 982 that I think I can fit to it, just have to get a different retaining bolt from Numrich, and I want to put a newer speedfeed forend on it.  I've seen a picture of one that a member here had with a speedfeed stock, so I was wondering if anyone knew if the current 870 speedfeed stock would fit?

This is one of those things you just have to try to see what will or will not work.
The Howa/S&W/Mossberg 3000 was a close, but NOT exact copy of the Remington 870.  
Some accessories will work, some won't.  
As example, the 870 magazine extensions will not work.