Anti Squeal Kit vs Springs?

I'm taking my car into the garage to look at a problem with poor MPG and it's obvious the offside rear wheel is dragging/sticking.

I've been doing a bit of research and i've seen two things and I'm not sure if they are doing the same job.

I've currently got the antisqueal kit fitted to my car which looks like this:

http://briskoda.net/forums/topic/138620-mooing-rear-brakes/

now, while searching about for some info to give my my mechanic, I found this:

http://briskoda.net/forums/topic/137832-handbrake-cable-issue-on-my-vrs/page__st__140

Does anyone know if they are fixing the same thing?

I'm 95% sure this is causing my MPG issues as I've already raised it in another thread.

Appreciate any responses.

Regards