Slower 2D with the 4191 drivers is a known problem. Since you installed from tar files, see if installing 3123 works (you shouldn't have to get rid of 4191 to do that, though). The one difference to watch out for is the alias in /etc/modules.conf -- for 3123, it has to be NVdriver, where for 4191, it has to be nvidia.
The 3D acceleration box is grayed out because that program doesn't understand how to do 3D for nVidia cards. If you're loading the "glx" module, you'll have 3D. You can check by running glxgears -- if you get decent FPS (like in the thousands, probably), then you have 3D.