welcome mate...just curious how you stubled upon the site?
Anyway..like the other said the two letters (EB, XB etc etc) just stand for the models code..kinda..
1987 - XF
1988 - EA
1989 - Still EA
1990 - Still EA...I htink series 2 came out sround this time
1991 - EA2
1992 - EB
1993 - EB
1994 - ED
1995 - Maybe ED still but definatly EF
Ok so now we are up to BA falcons...Im not sure why they are call XX, most likely pin the tale on the donkey or somehting.
As for XR6, thats just a variant of the falcon itself. For example the base model is a XT (thats not a model code.grr this is getting hard to say), then comes a Futura, Fairmont, fairmont Ghia (luxury falcons), then it gets sporty ala XR6 and XR8.
Then comes FPV cars...but for that you can just check out www.fpv.com.au
In essence they are very pretty and quick XT's.
I hope I haven't confused you more. There will be people here that probably could of said that in one sentence...lol..sorry