looks better.
Type: Posts; User: old'uns
looks better.
there won't be a White substrate as such, next layer down from the Black vinyl is glue.
Primer 'may' react with either of those surfaces anyway.....you could just put the new layer over top, finish...
the cracking is purely the age of the vinyl, heat cycles etc.
Pain in the *** to remove, even with heat gun only comes off in small pieces and leaves lots of glue behind and a lot of cleaning up....