Replacing window channel weather strip?

Just wondering if anyone here has replaced the window channel strip that goes between the door and the window. If you have can you give me some tips on installing it, at 42$ per side I want to know what I'm looking at in terms of difficulty...I'd rather not tear my door apart again if I don't have to cause I'm hoping it can be put in place with the door pannel intact.

Thanks man I know what your talking about with the car wash situation, just seems like a lot of cash to layout I really want to know how the quality is and how difficult the install is.