been there twice, i understand when you buy fiberglass parts, usually some work is needed to make them fit,..sanding, heating, filling holes, not cutting parts into 4-5 parts only to fibgerglass them back together,...
i have a 2004 sti with some fiberglass parts and carbon fiber parts and all of them FIT SPOT on with no work
1.
http://forums.pelicanparts.com/paint-bodywork-discussion-forum/555943-anyone-have-fitment-issues-renn-speed.html
2.
http://forums.pelicanparts.com/paint-bodywork-discussion-forum/560580-another-renn-speed-fitment-issue-what-do.html
good luck, its a pain, but its worth it in the end i guess