No worries - I did a little bit of reading up on the subject some time ago.
I did actually forget to add one category in the line up as there really are three, other than the SB/BS choice!
Metabo BS = Bohrschrauber = Drill/driver
SB = Schlagbohrer = percussion drill/driver
L/ (Li) = Lighter allrounder (no Impuls model available) and usually sold with Compact battery.
LT = Allrounder version i.e the new "standard" as compared to the older drills. Impuls available.
LTX = eXtra Torque with some weight penalty and the side grip. (almost double the Torque compared to the older drills)
Quick = Fastfix/Festool style chuck removal
BL = BrushLess
Impuls = Pulse function
So a mouthful of the above would read:
BS 18 LTX Quick BL Impuls and decoded as = Drill/driver, 18V, lighter allrounder, extra torque, side grip, quick change chucks, brushless motor and Impuls function.
Variations are SB for percussion drill and lesser acronyms if it is a scaled down machine.