Here is the XP needed to research the new line of American tanks, excluding unnecessary modules.
Tank cost / tank cost with the necessary modules:
Pawlack Tank = 28,550 XP (the experience can be accumulated on the T1 Heavy)
M-II-Y = 43.350 / 97.050 XP
M-III-Y = 89.800 / 215.650 XP
M-VI-Y = 163.300 / 414.650 XP
M-V-Y = 194,000 / 675,250 + 52,000 to research the top gun = 727,250 XP