Hard Drive. Help Requested, Newbie enquiry Options

[Foxyphil]

I have an emac G4,1 Ghz, running osX 10.39. Also recently purchased Focusrite Saffire, bundled with cubase le. Its clear to me that my mac just doesnt "do" 192hz, but I want to try to record files at 96hz. Doing this currently uses up a huge ammount of cpu.

I plan therefore to get an external drive, and will prob go the firewire route, maybe with USB2 compatibility. My question to experienced users is this. Is there any possible DISadvantages at getting a 300 or 400gb drive? Is it possible that an emac couldnt "hack" that ammount? The prices dont seem that much more expensive (I was thinking either Seagate or Carrilion) than for 100 gb. To be honest< id rather not have to upgrade any more hardware for at least a year or two - hopefully longer. I would actually like to try making a few tracks now.

Any input would be great.

Thanks in advance and thanks for great site too.

Phil