to answer your question, definitly slower but not that much. maybe 1 second at Roebling and maybe more like 2 sec slower at Daytona. Im not 100% sure at all ive never raced either of those tracks but i do know aerodynamics are pretty important atleast in road races.
At Daytona a few years ago I tried taking the sidepods off my F-125 laydown shifter during one practice session. I lost 21 mph off top end and my lap times were nearly 10 seconds slower. I had tried it many years ago (there used to be a 20lb weight break for no bodywork) on my piston port laydown at a tighter track (Hallett, Ok), and lost 3 seconds a lap. I’ve found aero comes into play at about 55-60mph.