well, heres my thoughts, since you wanted input. if youre going to use that airdam, leave off the rear bumper. ive seen the type 3/240z rear bumper combo on other cars, and i dont like the look for one reason. they dont match!! i think it looks terrible.
on the other hand, with your modifications it may match well and look decent. is it possible you could cut out the bumper part, and graft on a FG 240z bumper? if it could be done, i think that would look best if you want to use the type 3.