Since Singleplayer does not have events for most cars in the game, and Featured Multiplayer is limited to 2 Open Classes and 4 Spec Events, why not give players another place to level up their cars outside of Free Play while also providing rewards some wouldn’t want to miss?
Featured Rivals Events already exist and they rotate on a weekly/monthly basis, but are limited to just 2 cars! Or 3 if you own the VIP DLC. So why not increase that amount by providing Featured Rivals Events for more cars, and make them rotate weekly or even daily? Not just the current recycled Spotlight Car, but also other cars that may be underused or even forgotten by the game itself. Participating in those events would be a great opportunity to level up those cars, especially when you really don’t want to play Forza as it was always intended to be played by spending Credits on Upgrades, and it would be the first ever reason to drive them in their stock form. There should also be extra participation and top percentage bonuses for players, could be in the form of Credits, XP or even CXP.