In 1997 (a year where even McLaren stuck a low drag "longtail" on the back), Nissan chose a low downforce light weight set-up.
The plan was to create the same corner stability with a lighter car and better "mechanical grip".
With the smaller restrictors straight line speed would also be better.
Come Pre qualification their speed was indeed phenomenal, even though as Martin Brundel noted dryly " Tthe car was still a real handful in the twisty stuff".

With the June race ran under higher temperatures, Nissan couldn't match their may qualification times. Worse was to come as one by one all R390's suffered gearbox cooling trouble. After a promising start 12th place was all that Mr Walkinshaw and his crew could salvage.

1998 and Nissan was "back with a vengeance", TWR had worked hard on the R390's reliability and had done a "McLaren" by adding a 13 cm "longtail. In full endurance mode the Nissans concentrated on race set-ups while the likes of Mercedes, Porsche and Toyota gunned for pole.
Their reliability no longer an issue, Nissan played a waiting came in the race. The only problem was that with Toyota and Porsche pressing each other on, the R390's race pace was just a bit too slow.
After 24 hrs the leading Nissan crossed the line 4 laps behind the winning Porsche, but at least it could make it a formation finish with the other R390's.

Nissan R390(LM GT1 1997):
Length: 4590 mm, Width: 1990 mm, Height: n/a, Wheelbase: 2710 mm Tyres: Bridgestone Wheels BBS 18'

Nissan R390(LM GT1 1998):
Length: 4710 mm, Width: 2000 mm, Height: n/a, Wheelbase: 2710 mm Tyres: Bridgestone Wheels BBS 18'