Turnbuckles, CVD Bones, Arms and towers will be different, due to size as mentioned... T5m uses front axles with more offset, and the rear wing mounts (B5m)/Body Mounts (T5m) will be different ...
Both the 3 and 4 gear trans will fit either, from inner hinge pins in on front of both the same, same for rear (except towers/shocks) ... C &D mounts the same and a good variety available, rear shock bodies on T5m are 36mm rear/27.5mm front ... B5m are 31mm rear/23mm front ... there are two different versions of rear axles, the B5 and the B5m Team kit used the standard, and the B5m Factory Lite and both trucks used the HD ... Front Chassis plate same on both, but the Chassis Cradle is different on them, as T5m fits the longer T5m chassis plate ...
Interestingly enough, there is a B5m Factory Lite currently listed on eBay, that has everything mounted on a T5m Chassis Plate, the only difference is the chassis plate itself, and the chassis cradle ...
If you have any questions just ask, here or PM me if need be ... I have had a few dozen of them
Edit to add: ... I mentioned the two different rear axles, although both will 'fit' either application, and are identical other than diameter ... which is important because it will determine which hex adapters you can use on each ... there are many more options available for the HD size rear axle ...