An addition Piece

All the time ive seen an MPC2000xl in a magazine, i've never seen it by itself, its always this little box towering over it, I was told that it was some kind of filter piece where u can filter the samples and things... any one know what i'm talking about? Anyone care to elaborate?

Yes, that little towering piece is the MFC 42 Midi Analog filter, and that what it does, filters sounds, samples, etc. Do a search on this forum and you can find out more about it.

I had a quick test of one a couple of weeks ago I didn't think much of it but I only had a quick play

Yeah, I heard it was kinda overrated, but that's just hearsay. Myself, I just filter thru my mixing board and my pc (Audition) and back into my pc. You could get decent filtered sounds by copying your sample/sound, turning the frequency down between 0 and 20 (under shift +6, params) and turn the resonance up to, say between 5 and 10. Take that sample and layer your original sample on top of it. Try it out if you haven't. I did it for years until I started messing 'round with the pc.