I was just thinking bout doing the same thing.. im sure it is possible, would prob just be ALOT of work. you would have to remove the badge section from the ph2 bumper and mod your grill or the ph2 bumper more to fit it. then you'd have to mod the ph2 bumper round the ph1 lights and to fit to the arches properly... in short, unless you have cash to splash out, rather just spend half the cash on modding your current bumper. It at least fits properly as is.
Good luck tho on whatever you decide to do