You could in theory keep the TVN's on a USB stick as they load into the T2's memory.
I think it's only about 4mb internal for your own wavs (I know it's small) before adding any extra dimm chips in there, so any huge sized sample wouldn't work unless you add some extra memory. The breath noise should only be small anyway when it's a wav file.
If you do get any extra memory don't go getting 2 lots of 512mb as that's overkill.
2 x 64mb or 2 x 128mb chips should be enough because it takes ages to load in large samples anyway.
Hard drive is great for doing your own recording on and saving custom voices etc. If you don't plan on using one to record your own compositions onto, a decent sized USB stick would still do the trick if you just want to load and save sounds/styles.
I've got 128 TVN sounds (which is the most you can load into the T2 in one go), 800 styles (most edited and some my own) about 600 voices that I've edited and loads of my own all stored onto a 512mb USB and I don't even think it's used 100mb of that.
All of my sounds load as soon as I turn on the T2 in less than 10 seconds and any of the other sounds and styles are available from the USB stick at the touch of a button, very quickly.
I can of course put these onto my hard drive to make them load quicker but at the moment I'm editing loads so it's easier to have them on USB to get back into the PC.
It's all good stuff and easy to use and set up, you'll love it.
If you need any help and you use Skype, myself, Scott Yee and some others are on there almost every day.
I'm Craig_MrT2