REDACTED
You mean just leaving the "F" headlight assembly attached, and not the rest of the fairings? It's been done - search around for it (I'm on my phone so it's a pita to add links).
If that's what you're looking at doing, I don't think the wind will be much of a problem. Unless you're riding in cold weather, of course. Your top speed won't really be affected either - look at the top speed of an E model and an F model. Just stay away from Bonneville.
If you decide to go for it, take lots of pictures and ask questions! And welcome to the site, Matt.
Many have converted their GS500F to naked bikes without fairing. Here's an example of one:
http://gstwins.com/gsboard/index.php?topic=21212.0
Some have retained their GSF headlights like this one:
http://gstwins.com/gsboard/index.php?topic=39815.0
I use/used a big NC Plexi 2 windshield on my 97/02 GSs winters but change to a smaller Spitfire shield summers. Most of my 400-500 mile Interstate days travelling to the mountains to play were made with the smaller Spitfire shield travelling 70-80 mph indicated and I found it comfortable. Only time I ever opened up (110 mph indicated) my 97 GS was with the big Plexi 2 and 240# (then) me onboard, it was solid and steady all the way but on a very windy day the smaller Spitfire shield is less affected at higher speeds.
(http://www.gs500.net/gallery/data/500/summer-winterGS.jpg)
Where is a good place to get a tinted shield for a 04?