layered coloring effect

Hello FCP.co,

Registered here to ask advice on a matter that's been bugging me for a while.

I'm editing a promo music video for a friend - sequencing and basic color corrections is done, however before finalizing it he got a new idea, based on the following video:
vimeo.com/71792711

You can see an additional layer running through the whole video to add some gritty, random colored feel, more specifically at 1:16-1:18 and 2:13-2:16
Also, the coloring effect which I believe is added in post as well and you can observe at 00:09-00:10 is something I'd be happy to achieve separately.

As a first step I've modified my color levels so it matches this video (low blacks and whites and heavier mids generally). How would you get around achieving this feel? I have access to many absract videos with bright colors and movement but could not get results by trying to add them as overlay and playing with the composite modes. Stuck at this step for a good week now. Is this the matter of getting the overlay video clip right and I havent found the right one?

I'm a novice in editing and plan to progress beyond this level on the back of this project hence me welcoming the challenge but asking for your input. I can post some screen caps from my project later today if necessary.

I'm using Final Cut Pro 7.

Any advice is greatly appreciated!

JB