I didn’t notice this when installing mine, but I believe the pistons are steel or stainless steel, whereas most OE calipers are going to be phenolic (plastic) and therefore thicker. With the piston contacting the backing plate evenly, I don’t see it making much difference if any.
I would recommend having a die set on hand when doing the install, for some reason both flare flare nuts (vehicle side) came out hard and the threads needed to be cleaned up.
Also check your wheel weight clearance before test driving...spinning mine on the lift, there’s only about 1/16 of an inch clearance between the caliper body and wheel weights.