I think I will go with the full thermal tights underneth my mtb shorts. I can remove the liner from the shorts so I think that will work great. Like alot of cold weather riders the upperbody is my main concern. I think my sleeveless cold gear compression shirt will keep my core nice & warm but Im still stumped on the whole layering thing. I thought you supposed to wear cotton layers over the moisture wickering shirts. is this true? I just want to get the whole layering thing in the right order to obtain maximum performance in the cold. Also do arm warmers work good or should I go with a full sleeve thermal shirt? I thank everyone for the imput so far.