Tank discussion

[Ravenheart]

Hello everyone, I am developing a browser based tank sim. If any of you have played BiteFight you will understand how it will play, for those that do not know it:

The idea is that users will start out with a WW2+ era tank(say T-34,or a sherman) each user will have a link which when opened by other people will give him some renown/fuel which he can then use to either upgrade his tank, or fight someone else.

Now I wish to make the tank representation as real as possible, leaving out unnecessary details, for example the type of metal the engine block is made of. But I don't wish to dumb it down to simple "Damage" "Defense" "Health" properties.

So any way I need some expert information as to what to include in the base design of the tank representation, here is my current setup:

Tank
+Turret
+Engine
+DriveTrain
+Gearbox
*Ammo
*Armor

The turret and engine I'm considering complete but if you have any suggestions for them go ahead.
The DriveTrain I haven't even started because I really have no idea what to include for it(maybe make a Suspension class?).
Gearbox is sort of complete I just don't know if its worth adding more detail to it without making it overkill.
Ammo is not complete as I was wondering whether I should include whether it is HE or AR or any other type of ammo, again your suggestions will be great.
Armor I also think is complete, but want to replace the "Defense" property with protection against different types of ammo, so I'm at a stalemate because of the Ammo class.

Now keep in mind none of the components will determine the final stats of the tank, they will just add to the tank's base stats.

Thank you for reading