Visibility/Invisibility returns big time

Vallter: 1) There are no invisibility cheats\hacks\bugs. You can face lag problems or camouflage feature. Also take in count that different tanks have different radio range and field of view. Also please contact us via http://support.worldoftanks.com/ and we will try to fix your connection issues together.
2) Just changed D51066 turret to D51072 on M4 Sherman and received +60 to total amount of Hit Points
3) Thank you for your opinion. I'll pass your suggestions to the game designers.