Letty acquires the car, likely from Sean Boswell, Twinkie and Earl who Dom sent Tej and Roman to meet to get cars, at some point prior to arriving in Tbilisi and outfits it with a magnet in the rear that was obtained from Jakob's truck.
Letty drives the car in the final showdown in Edinburgh with Ramsey beside her and uses the magnet to take out cars in Jakob and Otto's convoy as well as causing powerlines to break to stop the police from chasing after them. To take out Otto's henchmen who are attacking Jakob, she uses the magnet to catch one of their BMW's and throws it at the henchmen, to which Dom then pushes the car under Jakob to break his fall.
Letty and Ramsey continue to follow the convoy until Dom successfully destroys The Armadillo and the battle comes to an end. The fate of the Nova is left unknown after those events.