T-90 is an upgraded T-72 with a new name. T-80 is a different animal from a T-72/90. Kirin makes a T-90 conversion/turret for the DML T-72 kit. My local shop carries(carried?) it for about $40.
T-80 is made by Lindberg (avoid), DML (OK), Skif (best of the three) in 1/35.