Originally Posted by Gruppe-S

I think the flex section is usually the culprit. Also depending on how it is installed you might have a bit more room here and there. If it's hitting try reinstalling it! The Megan one's however usually do have a bit looser tolerance. We had the same problems with the first generation Helix ones, some fit some didn't, basically if it's super tight sometimes the install will cause variation. The Helix V2 76mm will fit your ACD 05+ car fine though.

Cheers,

Gary
Gruppe-S