Important Notice To All Drivers
Click the reset to default option for every setting on the car and you will be able to enter a tuning prohibited room. Be aware that some of the tuning pages have more than one reset to default tab. You will have to select all of them that the game will let you select. You won't see anything change but it seems to tell the game that you are running stock settings. I don't know why it shows the nitrous message but it goes away after you reset all car setting to default.
I would assume this is due to the fact that some factory settings have been changed on cars with the new update. I haven't checked a lot of cars but I have already noticed the rear toe settings have been changed and the camber settings have been changed on some cars.
Cars that are acquired after 1.09 do not need to have the reset to default option clicked to enter a tuning prohibited room.
Just to be sure, I suggest that you set up a lobby with tuning prohibited and check your cars before Sunday night racing. Hosts will not be asked to wait for you to go buy another car if you can't get in. Take the three minutes to open a lobby and check your three cars so you don't waste three minutes of everyone else's time on Sunday night.