So Zone just came out with a 4.5in lift that has full rear springs B-) the rearspring pack is a 3in pack that they add long shackels on. Will this alow as much spring traval and flex as a shackel relocation kit?

Probably not, but the relocation may not get you the 1.5 inches you are looking for.

Yes it will give you the flex. A shackle relocation kit is used more to get you at that 45 degree angle for a smooth ride. I think my RC relocation kit gave me maybe 1".

Long shackle and relocation box = more flex than your shocks can handle