Hey mate, in regards to Catless DP, there wouldn't be too much of a difference between the two you've listed. In regards to pricing, VRSF can be had for about $600aud shipped. Fitment on this product was improved in the V2 version, as many of the original iterations of DP for the N54 had clearance issues.
As for install, it's a difficult job and many of us have it professional installed for $400-$500 (4hr shop time). On jack stands and with tools at home, this might take 10 hours!
