Doing some research
 

here the last few days about spats, deflectors and such and it seems the problem to overcome, or at least reduce the effect of is the bow wave.

It would seem an easy fix with just a horizontal splitter mounted at the bottom of the front fender. Then you might reduce the 60 degree airflow deal at the bottom front of the car, and actually be able to use deflectors directly ahead of the front tires.

http://wiki.seloc.org/a/Image:Splitter.jpg

What say ye?

Imo, not based on any hard data, I would be skeptical about it. It looks like they create an increase in the front high pressure zone, increasing overall drag more than is reduced by eliminating some of the flow that goes under the body. catamaran style deflectors that work more gradually and also fill up some of the low pressure are behind the rear wheels would be an ideal approach imo.

splitter
 

My thought is that NASCAR allows the splitter for safety reasons even though it actually violates the cars body template criteria.
The sides of the car provide the most direct route for the air to go,the bottom is off limits for safety reasons,so the splitter forces the air around the car,where it cannot produce vertical lift or drag if left to go under the car.
The thing about 'street' splitters,is how do you keep them on the car? They violate the approach angle of 16-degrees and even with careful driving,it's a matter of time until you tear them off on a driveway ramp.
You could follow Volvo's lead and make them 'active',deploying only when out of danger.
Re-profiling the nose accomplishes same thing,but there again,you've got to look at clearance.