I tried to tune a couple FE cars and got a message saying the file is locked and if I proceed the default settings will be applied. Or something to that effect. Can FE cars be tuned and do they retain their bonus perks?
Modify most of mine because in standard form you will come last in every race. I always get the perks 50/50CR etc this just means any tune/upgrades that come with the car you lose. So it is the same as buying a car from the auction and going to tune or upgrade.