To me, the overall answer is no.
Why?
When started up, OFP checks and loads up every addon in your Addon folder.
So every addon is adding to the memory usage, and allowing less memory to be used when the engine start its rendering work.
So yes it will affect framerates, but to be honest, in my experience the difference in framerates between having a full addon folder and a clean one (OFP install only) is so negligible as to be unnoticable.
So the overall answer comes out as no.
Confused? .... no? I'll have to try harder next time.