Tom, I suppose they could and I know this is all speculative, but I'm guessing you'd have to run a "spec" filter that provides a known amount of restriction. Otherwise, people would go with less restrictive designs and I think all you'd ultimately have is a bunch of cars that are running just a sfast as they were w/o a filter. A lot of installations probably wouldn't allow space for a spec filter with a set size as so many installations are different, e.g. under the header, sticking thru the hood, behind the grille.Rod, you don't think a filter company could resolve this issue?
I've seen them on SuperStock pulling tractors running boost levels as much (and more) as these cars are using.
That's why I'm suggesting a turbine inlet restriction. Most applications use a weld flange with a clamp anyway for quick removal. Make the restrictor a part of the weld flange. Make the turbo work harder.
Again, I'm trying to think of a way that's easier for the tech people (they usually aren't able to measure the compressor wheel inducer anyway, nor do most of them know the difference between an inducer or an exducer) and as simple and inexpensive as possible.