This build is looking really good. I originally was going to model the Jorge chest piece but after looking at all the extra pieces it had compared to other chests it turned me to a simpler one. So definitely giving ya props on that. Good looking chest and I have noticed more people going with this CQB helmet, you could try doing a vacuform visor like people do for the ODST and Pilot helmets, if you are brave LOL.
Also, how did you get that "dirty" look on your helmet? Like what technique, because I have not found a TUT on how people do that and yours looks exactly what I was wanting to do.