I recently picked up a couple of IIc+ off eBay, and you really need the external 5.25" drive to be useful. Unless you're looking to run AppleWorks, in which case the built-in 800K 3.5" floppy and 4MHz would be better than the original IIc. And as Sean pointed out, it might be cheaper to just get a IIc+ than to retrofit a IIc with 3.5" and a ZipChip (a rare item). Jimmy