Don't get it confused... There is
GTR
GTR V-Spec
GTR LM
GTR = Standard GTR form
GTR V-Spec's were heavier in weight, upgraded suspension, tyres, wheels updated ATTESA-ETS System. Nothing too special. But still a collectors item.
GTR LM = In 1995 Nismo developed the Skyline GT-R for endurance racing with a pair of JGTC specification R33s for the 24 Hours of Le Mans. In order to meet homologation regulations, a street legal version had to be built, although Nismo only required one example to comply. The two racing cars were able to achieve some success at Le Mans, with one car achieving 10th overall, and 5th in its GT1 class, being beaten only by the more developed McLaren F1 GTRs. For 1996, the Skyline GT-R LMs would return, this time carrying enlarged RB26DETTs displacing 2.8 litres. Again competing in GT1, they would finish 15th overall, and 10th in class. However, Nissan chose to abandon their production-based Skyline GT-R LMs in 1997 and instead turn to the purpose-built R390 GT1s. In honor of the success of the Skyline at Le Mans, Nissan marketed a limited edition R33 referred to as "LM Limited", only available in a Competition Blue.
REF - http://en.wikipedia.org/wiki/Skyline_gtr