Bump to an old thread. Volant/Corsa must have revised the intake because everything went together wonderfully for me. The only complaints I have are as follows:
-Airbox lid could fit better, screws do not end up in the center of the holes. I assume this is a molding issue when the box is manufactured.
-Throttle body to airbox tube could be longer. There is about an inch of unused space when the couplers are on. Kinda puts the clamps near the ends of the tube.
-Silicone coupler that connects the "Ram Air Scoop" to the airbox needs to be shorter (I had to trim). I believe that its 2.5'' and needs to be more like 2''. With HID headlights, the scoop has to be able to go as far back as possible and with the coupler being too long, it restricts how far it can move back resulting in the headlight not being able to go back in fully.
-Coolant overflow cap needs to be more secure. It clips in, just remains pretty loose compared to stock.
I really didn't have a problem with the instructions. They are super detailed, just don't list out the steps to take. If you are mechanically inclined, you won't have an issue.
First test drive, there was a lot of bellowing noise between 1400 rpm and 2000 rpm. After a few days of driving, that seemed to have gone away. Exhaust note seems to have become more lively, which I personally like a lot. To soon to report on any mpg increase.