the glow is done by not a lot air pressure living out the exhaust cause to glow bright reddish orange color or even purple . 
you can make hot dog with that thing who lol 
They will probably add that in time.
Doubt this will be in the game tbh. In reality how many production cars do you see with “exhaust glow”?
Somebody will probably mod it eventually tho haha
What Drummerdude says, it has so low priority that it doesn’t fit onto our todo list 