No, we don't use NWjs code protection and so there is no performance hit from that. If you enable minification on export, you get good code protection anyway from the obfuscation.
There really isn't any good reason the performance would be significantly different after export - in fact I'd expect it to be better, since it has the advantage of using spritesheets after export, and a lot of preview-only JS code is stripped out.
Thank you for taking the time to answer.