What do the MPC 4000 Studio D have versus MPC 4000 Plus?

I was thinking of buying a MPC 4000, but some places have them listed as MPC 4000LE or I may see MPC4000 Studio D or MPC 4000 Plus. What's the difference between those to

Sean @ Akai wrote this on another forum:

"There are now 3 models of MPC4000 available in the US:
* MPC4000plus: 272MB RAM, 80GB HD, CD-RW, IB-4D
* MPC4000 Studio A: same a MPC4000plus, plus IB-48P (8 extra analog outputs)
* MPC4000 Studio D: same a MPC4000plus, plus IB-4ADT (8-channel ADAT digital inputs/outputs)"

So it's basically the same machine but with options included. Notice though they come with 80GB HD now (mine has a 30GB I think).

Thanks SpikeyMan you helped me out a lot.