wow, good job ! that's not an easy way you chose, but it's promissing !
For the side air intake in the front spoiler, you'll have to insert a small edge which comes a little out the air intake itself, due to the fact the 2005 car is larger than the 2004, then all parts follow the extension, spoilers too.
I have tons of reference pics for the 307, would you have some ?
I only need and email address and I can send a Win Rar file.
if you are interested please use this address:
[email protected] (higher sending capacity then my principal email address)
Phil