The original fog duct design was considerably different than the Powertrix version. Yours don't seem to offer any significant design differences over Powertrix. I've never had fitment issues with any of the Powertrix ones, and I doubt you'd see any measurable increase in airflow with your design, especially since they're not really directed toward the intercooler any more than the Powertrix ones.
Cheers, JBrobst
"A life spent making mistakes is not only more honorable, but more useful than a life spent doing nothing." George Bernard Shaw