I was told it adds a lot of down force so not sure if that would slow the car down. I'm sure it was design for use on the track not the drag strip.
I say put it on and let it rip. Take it off (its only a couple of screws) see if your time improves or slows you.
The reason I say its designed for...
The car I ordered in Oct was never built
Not sure why, but I had the same paperwork it shows it was ordered
I hope you had better luck then I did
If you want one find a dealer that has one and buy it
Koons Ford in Florida seems to have a couple also
Back in March when I bought mine he had 5 Gt 350's on his lot
one Kona blue but I don't remember if it was an R
For some reason they get a lot of Shelbys
I had ordered mine in Oct 2019
Got tired of waiting so I bought the exact car that I had ordered from him
I just got home from Track Attack...