1/24 scale model upgrade parts?
 

Ive got these Transformers Alternators (1/24 or 1/25 scale) and I want to spice things up a bit, like adding/changing spoilers, vents, gorund fx kits, etc.

Does anyone know of a site where I can just get upgrades like these with out having to buy entire model kits?

(Mods, if this is in the wrong section pleas move)

Hlj.com might have some in their car models section. Some may be resin or photoetched brass