Not to mention:
M5 drive by with Thompson/bren
Fast M10 to counter enemy vehicles
USF can also rush a fast (4-5 min) M3 Assault Halftrack with cavalry riflemen inside. It can be strong and useful at times, but it never seemed like "oh my god this is so broken!" to me, and I have used it countless times already.
It may be fair however to lock the quad mount behind the t3 brit building