"Шокирующие разоблачения" 
от Damian Ratka (Damian) - здесь.
1. Most Leopard 2A4's made (also older A0-A1-A2-A3) use B technology armor. During some tests we confirmed this armor is weaker than armor of T-72M1 or our upgraded T-72M1, the PT-91. You can guess we were kinda dissappointed. Only some last production batches of Leopard 2A4 had C technology armor, and last 70 or so had D technology armor same used on Leopard 2A5 and Leopard 2A6... however we do not have these tanks.
2. We also discovered a fatal flaw in Leopard 2A0/A4 chassis design, the bottol of the hull sides where suspension is attached have a structural weakness, which means you can't up armor tank to the weight of 60+ metric tons, otherwise after some time tanks chassis will start to crack.
This means that to upgrade tanks, you need to literally cut off entire hull lower sides where suspension is attached, probably also cutt off hull belly, and weld new ones that are strenghtened. This is obviously incredibly expensive, this is why Leopard 2PL do not have addon armor on the hull. And there are some rumors, we might have also problems with A5's, but I have no solid confirmation yet.
By the way, we found out similiar problem with turret upgrade, lots of cutting and welding again to bring A4 turret to 5 standard. This is also why cheaper Rheinmetall won with KMW.
3. AMAP-B armor was tested on the prototype, can't speak about it, but let's say, it was all very dissapointing, if the informations I have are all correct.
И комментарий от Jarosław Wolski (militarysta) - здесь.
1. Yes, mostly true.
PT-91M/M1 have better vs KE armour then Leopard 2A4 and as base armour - mucht more weaker then L2A4 against HEAT. But PT-91M/M1 whit ERAWA-2 is mucht better protected then Leopard 2A4. Sad, but it's fact. But from the other hand - Leopard 2A4 outdated PT-91 in all other aspects and tank crews don't event want to lisen about T-72M1/PT-91/Pendakar tank. They just want's Leo-2.
2.yes, it's true in case old 2A4.
3.No, not true. AMAP-B is OK, "base armour" in Leopard 2A4 is shit -that's the problem. Whole protection accoding to polish PGZ shoud be "over 2A5 level" but on test WITU dicover that is not even on this level. Rest is classify but definetly AMAP-B is not problem...in relatio to weight is very good.
