I'm using DynaZip for an app I have to deliver outside of our organization. I am using InstallShield Express 5.0

The question is, where to place the DynaZIP distributable DLLs in the destination system?

In the same folder as the app [InstallDir]? (looks kinda cheesy to me for the user to see them outright in Explorer. Maybe my quirk but doesn't it look somewhat unprofessional?). Or should I place them in [Windows] (could have permissions problems for installation). Or maybe [CommonFilesFolder]?

What would be the best, most commnly used or recommended folder?
TIA