Ok .... here comes just a quick list off the top of my head.
U.S. forces - M4 (75), M4A1 (75), M4 (105) ....
M4A3's came into the game after D-Day, same with the 76mm gun tanks (I believe).
No Easy-8 suspensions at that time.
Commonwealth Forces - M4 (75), M4A1 (75), M4A2 (75), M4A4 (75), M4 (105)
Hope this helps a bit, if you need more info, just yell and I'll do my best.
Happy Modelling and God Bless
Robert