Can anyone define what the difference is in a J Spec versus other North American specifications please?

A J-spec is basically a Euro with Japan specific headlights for driving on the other side of the road. The headlights can be changed to Euro with the addition of the Euro lowbeam and lense.
Canadian spec car is a hybrid between a Euro and Domestic US spec car. Has headlight washers and DRL's and some have sports seats (like both my C-spec cars).

J spec = Japanese specification. Basically these are Euro spec cars ( LHD)with certain features specific to that market. Tom can expound upon better than I. Japan cars have been coming into Canada because their statute of limitations is lower than ours for an import to be legal without modifications in their country.

man you guys just know everything...;)

A J-spec is basically a Euro with Japan specific headlights for driving on the other side of the road. The headlights can be changed to Euro with the addition of the Euro lowbeam and lense.
Canadian spec car is a hybrid between a Euro and Domestic US spec car. Has headlight washers and DRL's and some have sports seats (like both my C-spec cars).my car was "supposedly" bought from a dealer in germany,imported to japan where a college student put 31k miles on it than a navy chief bought it and for the most part kept it in a shipping container for 11 years and than brought it back to the states and thats when i got it.is the V12 badging a aftermarket add on did BMW install it? and how do i id these J spec headlights?

Any v12 badging on any E31 is aftermarket. The V12 cars never came from the factory with descriptive badging. If the headlight lenses do not have an "Ecode" (E1 or E2, etc) molded in the glass, they are J-spec. If there is no lever to change the low beam cut off under the headlight cover it is a J-spec.