What is the difference between a Nissan skyline gtr and a Nissan skyline gts?

I take it your refering to the latest three ? i.e the R32, R33 and R34 models...... A very basic breakdown is..... GTST - Rear Wheel drive. GTR - 4 wheel drive (But not permanent 4 wheel drive, it uses a clever Atessa system to put up to 50% torgue to the front wheels when traction is lost). GTST - Displacement of 2.5 litres and a single turbo, rev limit is 7,000rpm. GTR - Displacement is 2.6 litres twin turbo, rev limit is 8,000rpm. The GTR exterior and interior in standard form is out of the GTST's league IMO. I have owned Both, and I much prefer my GTR.