Both the B&M and Steeda change the fulcrum point and the angle below it. The Steeda just changes the length greater and thus requires a riser plate. However it also has a longer handle negating any comparable advantage in the actual throw of the shifter.
Both are quality units and are a great upgrade over the stock shifter. You can not go wrong getting either unit.
BEWARE knockoff B&M shifters though. They are the ones notorious for breaking at the welds because of inferior materials and workmanship.
Also remember to NOT connect the centering spring when installing your new shifter.
As for the riser plate, is that something you made yourself, or did you buy it?