As Steve mentioned, when you buy the SEPST you don't get software anyway. It, along with cables and other essential stuff, are all optional at additional cost. One more reason I'd never consider buying an SEPST from Harley; I don't appreciate this sort of marketing practice to make your product look price competitive when it really isn't. Of course, the marketing folks at H-D would probably say that they stopped including the software and cables several years back because so many folks just had the dealer download maps or do the dyno tune, and the customer would be paying for cables and software they would never use. Only thing about that argument is that they didn't reduce the price of the kit when they eliminated the other stuff, so that pretty much exposes that BS for the lie it is.
If you're really interested, get the CD (P/N 32111-11 Software CD, $29.95) and see what it says about installing it on multiple computers. I wouldn't be the least bit surprised if Harley in it's greedy wisdom didn't find a way to restrict it's useage so one guy couldn't buy the software package and share it with his buddies. It's just not the Harley way to pass up an opportunity to stick it to the customers. And if you actually want to be able to communicate with the ECM, don't forget the cables. H-D's version only costs $39.95, I imagine you can replicate their offering at the local computer store for about half of that.
Jerry