Search vacuum cleaner Chaparral. Used fans to suck air from beneath the car. The ex-F1 driver said he never got to the limits, so far out of his experiences. I saw it race and it was just cruising around Laguna Seca, blowing off (literally) the other CanAm cars. It was banned...
So, the thrusters will be pointed up, providing downforce without the drag of spoilers and having this force available at even slow speeds as in the start of a drag race or through a tight corner at a race track. They would most likely be situated both front and rear and the thrust would be instantly apportioned depending on need.
The Chaparral, as I recall, used a beefed-up suspension and special high-load tires to cope with the downforce which I think was enough to stick the car to the ceiling even when stopped.
A Roadster equipped with thrusters would be faster than any other car with with similar power and would stop at a possibly dangerous G-force.
I just cannot see thrusters pointed out from the car, blasting adjacent motorists.