The front air duct will be going to the esc to help it stay cool at high speed. Been reading everywhere on how they heat up and die on people so that's the solution. Still waiting on the light weight flexible hose from china though for that mod to be complete.
The front of the car I had notice that the factory canard is very flexible, so I don't think it's reliable for 100+ runs.
This is what I did for more rear DF. Just add a hard rubber o-ring to the back of the wing mounting screw to lift it up in the back. Try one first to see if it's enough DF for you. Add two and you might scrape the rear diffuser so stiffen springs in the rear.
Also make a mounting plate for the rear body mount and wing. The body is very soft so this helps transfer the DF to the rear wheels. Do the same for the front, it's much easier.
With all the air going inside the car it's actually trapped in the rear and forces it downward right where the diffuser is so it'll create a bit of a lift and act like a parachute. I added vents on top rather than right next to diffuser.
Also slvr bullet I think this car is very capable of reaching very high speed if you have time, money and patience. Most of my mods here will help you getting more df. If you have any questions or need help lmk.