There are sound ROMs for the E-mu as far as I know that slot into the other two, er... slots but I think that doing so halves your installed sample RAM.
But I could be wrong about this so somebody please correct me if I am.
Gilles
E-mu E4K, Yamaha P150, DX7 Mk1 with Sycologic V2 upgrade, TX7, Roland JV1080, Akai S1000 & S2800i user