According to the most reliable estimation, the T-90S armor is equivalent or practically equivalent (in passive armor) for M1A1 and Leo-2A4 modification. However Shtora adds something too. It's enough good in practice considering relative few numbers of M1A2 and Leo-2A5-6 in the world. How M1A2's are already produced, anybody knew? The next Russian tank, which supposely will be produced starting from 2011 will have better defence than M1A2.I dont think the T-90 can have armor like or surpass the Chobham armor of the M1A2s.