Haha I see. Well I started out wanting to build a Block 2 but then after mating it with the MPL lower, I just kinda figured the MUR-1 would look nice with that lower. And then being a fanboy, everything went MPL from then on hahahahaha
As for the 553 vs EXPS. Looks aside, the 553 really packs on a lot of weight vs the EXPS.