I renamed my scripts folder and the severity of the frame drops seemed to decrease. I didn't get them as often and they only dropped to 25 or 30 fps. Then I renamed my mods folder as well and the severity seemed to go down even more, only dropping to 45 fps or so. But they were still occurring.
I guess this means either an issue with my game or with my system?
The last couple of forums post here on troubleshooting is about this issue. I think something is broken with addon cars right now, especially if your game has no addon cars and you start adding. Seems all the people who already has working addons have no problems.