"difference between the LM and the normal GTRs?"
There are only 72 cars in the F1 production ,there is 5 LM model 3 Gtr model, other just a standard F1 .diffrent is the front & rear down force kit including the full fiber material,anti-roll bar and full racing padel ... ( and they had to lower the horse power to fit the race regulation!)
ps: anyone please crrect me , if i wrong