One thing I'd love to see remade in Assetto Corsa is the 2004 Formula Gran Turismo Concept. Its aerodynamic package is based on those seen on the V10 screamers of that era, but has full slicks instead of grooved tyres, the driver aids that were last seen in 1993 before their ban, and a 3500cc, 60-degree Bank V12 producing 891 Horsepower at 17,500 RPM and 392 newton-metres of torque at 15,500 RPM in a car that weighs 550kg curb weight. (625kg including the driver assuming 75kg driver weight)
To put this car's performance into perspective, the official figures from the F2004 are 865 Horsepower at 18,300 RPM, and, based on Kunos' rendition of the car, 349 newton-metres of torque at 9000 RPM, from its 3000cc, 90-degree bank V10, and weighs 605kg with the driver (530kg curb weight assuming 75kg driver weight)
The Formula GT can lap Suzuka in 1:30, putting it roughly 2-3 seconds faster than Rubens Barrichello's Fastest Lap during the 2004 Japanese Grand Prix (1:32.270) in the aforementioned F2004, and wasn't beaten by an official F1 car until 2017 by Lewis Hamilton's Pole Lap, set with the Mercedes-AMG W08 EQ Power+ (1:27.319).
With Gran Turismo partnering with Red Bull since 2010 for the X1 series of concept formula cars, bringing Ayrton Senna's Lotus 97T to sim racing for the first time in 2014, and ironically enough, the same Mercedes W08 that beat this car's Suzuka record arriving in GT Sport just over a year ago now, I fear that this car may just end up falling by the wayside more so than it has done already; given that it isn't in GT Sport and we're still very much in the dark for GT7's full car roster.
It's a shame too, because this car is quite a looker, and even got some visual touch-ups in GT6 to bring it closer to the visual standards of newer cars; albeit not quite up to snuff with that game's full premiums.
Here's the demo run of the car in Gran Turismo 5; unfortunately the GT5 version of this car still has a lot of the PS2 artifacts in its model, and the demo run feature was removed in GT6.