Regarding profiles, I found Adobe's free DNG Profile Editor to be a nicer program than the X-Rite one.
As for the question why do we need them? Well if we think about it, the out of the can ones do not make any allowance for the lenses used, they can't possibly be neutral for all lenses, the only way you can normalise your output is if you normalise your input.
Hi, how would the workflow look with this? I am using LR4 today, will upgrade to LR5 soon. Will I have to convert my RAW-files to DNG ang applying this filter before importing to LR?
All the information you need, is available here -
Check out the documentation available on the DNG Profile Editor.