Dear Recon89,
As Mr. Jack's link suggests there are a number of "correct" ways to name the Tiger I.
I am in no way an expert on this subject but I speak some German so let me offer you my 5C on this.
Sd.Kfz. is translated to Sonder Kraftfahrzeug = Special motor vehicle or Special Powerful vehicle
181 is a sequence number.
PzKpfw = Panzerkampfwagen or simply Panzer translates to;
AFV = Armored Fighting Vehicle or simply armor/tank
The VI is more like a generation designation..
You have the
Panzer I
Panzer II
Panzer III
Panzer IV
Panzer V, Sd. Kfz. 171, Panther
Panzer VI, Sd.Kfz.. 181, Tiger I
Panzer VI, Sd.Kfz 182, Tiger II
The Tiger I is usually referenced as being either an Early, Mid or Late version.
The most striking visual differences between these are the road wheels and the commanders cupola.
With Kind Regards.
Utoshita