Well, i will try to do an overlay of some pieces of the interior of my car, i already do an mold using fiberglas of the original piece, add an clip to the back, apply to the car and use an silicon gun to apply the tweeter base. THere you can see the old place where im using the tweeter, but i want to move it a little ahead.
Another View
and another
after that i remove it from the car and use some cloth and use fibeglass+resin on it.
after like 3 hours i apply filler (i think that you call it bondo)
after sand it with 60 i get something like this
after the 2nd layer of filler and sand with 60 i get this
and you can see it in the car 
well hope like my job, its my first one, and is not finished already. i cant expplain too much because my english is not good, but at least i hope you understand what im saying
after that i have a few questions… can i apply the CF over the filler? need to use another sand paper? or will be ok?
i see a few holes in the filler, but its an overlay, maybe i dont need to fix it, or yes?
need to use some primer? or will be ok just over the filler?
well, hope someone can help me
best regards
Jose LUis