Or you can get the 4G iMod and save yourself a couple hundred bucks, and use an existing IC.
I'm sure there are sonic differences, but is it really worth the ~$300 difference?
I doubt it, unless you really want the extra storage space, or the use of the headphone out.
I don't really see the use of using the headphone out on a 5G iMod though, considering you paid premium for it, then you might as well reap all of the sonic benefits at all times.
Else you might as well go 4G and use the money you save to buy a smaller DAP for when you want to be really portable.
At first when I heard the announcement of the 5G iMod I was slightly disappointed, because it was only a few months after I'd gotten my iMod with the notion that the 5G iPod was not imoddable.
Just sheer human nature I suppose to want to have the newest/best, or distaste because your product has become outdated.
Looking back on it now, I don't really mind, because I highly prefer the using the headphone out jack for my IC instead of the dock, this makes the whole setup more "pocketable" for me, and I can use the lineout for other things like a battery pack when needed.
Just my 2 cents on an alternative.