Here's a roof I just finished...you shouldn't b able to see the holes on this one...

Here's how I did it:
- Sand te piece lightly.
- Put your filler or putty in the holes...make sure you actually "overfill" the holes...
- Let the filler dry (usually about an hour)
- Sand off any excess, while being careful to sand a flat finish down to the original plastic.
- I then gave each filled hole a little dab of Crazy Glue. (make a little bubble of glue on top of each hole...something you can later sand down.)
- Sand down the crazy glue once dry...(I left it overnight), again sand down to create a smooth finish with the original surface.
- Wipe the piece down...you won'tbe able to wash it because of the filler and the glue. (If you wash it I don't know what might happen...cause I wasn't willing to risk it.)
- Give the piece the first coat of paint.
- Again, sand down to make sure the piece looks smooth.
- Continue coating with paint.
Hopefully that helps...and I hope you don't think I'm saying yours doesn't look good...it looks awesome...but maybe this will help for next time! I didn't think Crazy Glue would work...but it did!
Great custom by the way...I didn't really see Dragstrip as the RSX...but it actually works.