So when I have SweetFX installed, no matter what directx I use, I get a solid 3fps... Anyone have any light to shed?

Solutions: http://reshade.me/forum/troubleshooting/498-solved-gta-v-crashes-with-reshade-17-1-sweetfx?start=48 - Crosire http://reshade.me/forum/troubleshooting/553-fix-for-game-crash-when-using-reshade-with-gta-5#4544 TL;DR - www.microsoft.com/download/details.aspx?id=36805 - Download that and see if it fixes your problem.

I should probably have mentioned that I'm on Windows 8.1. Also: i7 4690k and GTX 980 with 16GB DDR3.

Try posting on the ReShade forums and Crosire will probably help you himself(or one of the countless other individuals that know much more then me): http://reshade.me/forum/index

Will do, thanks.