Who gives a rat's arse about what NASTYCAR says or does! 
Do they have the infrastructure such as highly sophisticated wind tunnels and computers and do they have the superior expertise that F1 personnel demonstrate on a daily basis? 
Yes they do....
NASCAR teams spend millions on windtunnel time and CFD to optimise the cars. as they are so regulated, tiny differences count, more so than in F1. A NASCAR team is a huge operation. Typically a 3 driver team has between 8-10 cars for EACH driver. Then you have the huge fabrication, and engine shops, as well as the suspension side of things. It might appear to be a redneck sport, but the people on the inside are every smart cookies, that earn big money. Remember Nascar limits what and how the teams can use various parts, but the ideas they come up with to tune the cars would absolutely blow your mind. I went from working on F3000's during the day, to helping a Nascar (Aussie spec) team around the corner at night, to learn more about race car dynamics. As a result, I have a huge appreciation for what they are. I actually took small ideas across from each category, to help gain some speed out of both.
Back to the topic. The boot spoilers on Nascars effectively kill the lift off the bootlids on them, THEN they produce 200-300 hundred pounds of downforce, thats all. They are very agricultural in how they work. by nature they are a very high drag device, being simply an air shovel. All things being equal, in terms of lift and drag for a given angle, a wing always wins hands down. NASCAR only use them due to the sustained high speeds they achieve on the high banks, and at 200 MPH (320 KPH), 200-300 lbs of downforce is peanuts.......
A wing is always more efficient, as the airflow is reattached at the rear, resulting in much less drag. For a spoiler to produce a given level of downforce compared to a wing, it will always be quite steep. Although F1 wings can look like a 'barndoor' from head on, they are actually quite efficient. At places like Monza, the cornering speeds are quite high, and as aero forces increase at a squared rate as speed doubles, they don't need the big wings for the low speed grip, as at other tracks. Wings require a knowledge of their working range o get the best out of them, spoilers are simpler to understand, and adjust.
Nascar went back to the spoiler from wings, as the teams and regulators knew them intimately, and the the rulemakers could easily adjust parity between the makes, by simple spoiler alterations. The wings would require more work, and hence expense. Being lower in drag, the wings allowed very high terminal speeds on tracks like Talledaga. A spoiler instantly knocks 2-3 MPH off the top speeds in comparison.....
Big 4x4's are about as aerodynamic as a house anyway, what a stupid moron!
