Well, I did this about a week ago. I added the Roush fender cutout, they actually allow airflow throught the engine compartment. I found out that removing the fender liners is the way to go. It's a pain but well worth it.
I think it's a rare occasion if you can get 50% return on any "custom/additional" things added to your car, especially when dealing with a Dealership, but when they have the car on their lot it's like "one of a kind". Keeping that in mind I think somewhere around $60k as a starting point but...
Guys - So, back in 2014 I bought a brand new GT Premium with 6sp and Track Pack. I had no more than 1k miles on a new car and 3rd gear always ground going in. I even double clutched it and it still ground. I took it to my local Ford dealer and he pulled the trans and said it appeared that the...