Any modification or customization is completely subjective. Definitely a personal preference and the choice is completely up to the owner. It's obvious I'm a huge fan of customizing and modifying cars. And I get my share of criticism for it. But I believe in "make it whatever you want it to be".
That being said, are you asking for opinions or simply stating your desire to add a wing?
If it is opinions you seek, then mine would be to go with something smaller for a street car. That can be lots of styles, I'm just saying not as huge as the Dallara one. But your have done a terrific job building your X so I'm sure whatever you choose to do will come out great.