I repainted the yellow limbs to black using a permanant marker.
the yellow spoiler I painted blue and accented with black.

I repainted part of the body and legs black as well and did a little
work on the headlights.

The exhaust system got a little paint as well.

The gun is not an alteration the toy can already do that.

Finally I did a little filing on both the hands and tailpipes so that
he can hold them like swords.  it's so obvious I don't know why hasbro didn't
do this in the first place.  the swords add a lot of options to the toy.