factory colour codes are always good because its always easy to get a colour match if you need to touch up/respray panels in the future. Plus a fresh paintjob is always gonna look mint.
Im getting my r32 respryed in the same factory metallic black.
Give it a go yourself first mate. No harm in trying i guess. But like others have said, most a lot of fiberglass kits are a pain to fit. Jus a matter of CBFness lol