On ‘08, and up, the ECU controls everything. Spark, fuel.... the whole caboodle.
The only fuel control modifications I know if are put in series with the factory ECU.
They probably can add a little more power when dialed in, but all they really did for me was kick my fuel mileage to the curb.
This guy, http://ivansperformanceproducts.com/
says he can remap a Road Star ECU, but just needs a donor. To date, he hasn’t done it that I know of.