I don't think you need the unofficial patch (and I'm always leery of downloading files from strangers).
I have had success with editing "display.cfg" in the "TRON 2.0" folder. Set the following:
And voila. The menu won't be in HD but the game itself will be.
Editing the config files will allow the game to run in 1080p. But menus will be broken (some UI elements will be hidden off-screen), e-mails and help files acquired in the Single Player campaign will all be cut off at the bottom of the screen (preventing you from reading them completely), and cutscenes will always be stretched. The only way to fix those is to modify the game.
The Unofficial Patch will fix some bugs in the GOG version of the game (including not being able to achieve a final score of v10.0.3 in Single Player if you played a perfect game), and the Killer App Mod is (among many other enhancements) responsible for fixing the aforementioned issues in 1080p and other widescreen resolutions.
I'm a curator/creator of much of the fan-made content for TRON 2.0 (Killer App Mod being the most notable example), and I've been a part of the fan community since the game launched in 2003. In those 16 years, if there was anything "nefarious" about the fan-made content being offered, I'd think we would have heard about it by now. ;) GOG staff even tested the fan-made fixes with the GOG release of TRON 2.0.
Still, whether or not anyone wants to use unofficial fan-made content is, of course, absolutely their choice.