Originally Posted by: FlashyClamp5213 
Originally Posted by: ForbiddenBeef21 
Did you expect Koenigsegg to let some game developers borrow a car they only made one of?
As you have realized... the making of the sound of a vehicle doesn't necessarily involved with physical access to the vehicle.
This is also where the necessity of a good sound engineer comes.
This!
Look - let's not kid ourselves here. FM4 and 6 had a handful of cars. And most had their sound done right. At the time, they had some Caveizel guy working on FM4 and he's an expert known well in the game sound engineering industry. I'm sure his team did not have access to every single car in the game but they did such a wonderful job of faithfully recreating sound for each car, despite the console tech at the time.
In this day and age, and with the hardware they have, there's no excuse at all. They don't have to drive or rent every single car - they can spend a few hours reviewing the sound on each car via Car Review Videos, other POV videos, user reivew videos, or footage or races, high-speed flybys - possibilities are endless. Or just contact the manufacturer for some recordings.
If I can propose a solution from my keyword, they can certainly put in the legwork to get the sounds right. I researched the forums at length, and I have honestly not seen this many car audio complaints on any Forza games prior to Forza 6.