Can yu Install Multiple MBOXes or add 003 with MBOX?

I want to expand my inputs and output selection, when looking for a new interface at Guitar center that had 8x8, the guy said that it only works with Pro Tools M Powered (I use PT LE). He also mentioned that If I purchaed another MBOX or 002/003 product to expand my inputs, It would cause driver conflicts and I would be only be able to use 1 and only 1 interface. Does this mean that If I purchased a new MBOX with more inputs/outputs or a 002/003, I would no longer be able to use the MBOX i'm currently using now?

One at a time sorry

Correct, only one interface at a time can be used. You are maxed out at 18 inputs total for any version of Protools LE or M-Powered. Now if you're talking about just adding more preamps to a 003, using the adat inputs you can buy something like a Presonus Digimax FS.