I have an EMU 5000 sampler, I built in a IDE HD and it only makes a bit noise when I save a bank, but still its very quiet, ask the Comp dealer for the most silent one when buying.
I also plugged my scsi to the pc, and what you need for sending wavs to your sampler is a sample editor like wavelab. You load your wav in the editor and then you can get the sample transfer function in wavelab and send it. You can do this both ways, to and from your sampler to pc.
What I would buy if you have the A 4000, is an external SCSI cdr, cause the A 4000 has the ability to write its own cd's, so you can backup your complete banks on the hd.
Also the problem I have with cdroms you can buy with whole banks for your sampler is that I have to use an SCSI cd drive to be able to load them directly into my sampler, caise my PC completely doesnt understand those cd's, dont know how this is with the A 4000. But the SCSI CDR is probably a good buy.
You can maybe even build it into your comp and use the internal scsi connection of your scsi card in your comp, and then the cdr will probably be part of the scsi chain, and thus directly excessible by your sampler.