However, beware of the 2 seconds of being unable to move - only use it when it is able to be done safely. Likewise, Siege can be activated 2 seconds before reloading to optimize efficiency. Timing the switching between modes can actually boost the reload - taking a shot in Siege, and then exiting will make the reload have the normal time of the standard mode. Siege mode makes the gun soft stats worse, lowers the DPM significantly, and even lowers the mobility harshly, but dramatically buffs aim time (outweighs the soft stats penalty), dispersion & enables hydropneumatic suspension for an additional 5 degrees of gun depression. Standard mode features high mobility, great DPM, good gun soft stats but bad dispersion & aim time. Something of a weird cross between an STB-1 and one of the Leopard mediums.

Horrendous gun soft stats in Siege Mode, particularly moving/traverse bloom.

Rather bad gun depression on sides and rear in standard mode.

Very lackluster mobility and DPM in Siege Mode.

Lack of armor and compact modules/crew members creates massive amounts of crew injuries/module damage.

To get the most out of both modes, switching is required, and it prevents moving for 2 seconds.

Very good mobility in standard mode, can maintain speed easily.

Siege mode significantly boosts accuracy, aim time and gun depression.

Great gun stats - high penetration, shell velocity, DPM.

Panzer general wiki