I put on Zoomies over the winter - changed a few other things so I don't have apples to apples comparison. From what I can see they are the same as my Dynatech 2 3/8 to 2 1/2 steps.
I put them on because:
1. I needed new headers as the Dynatech were pretty beat.
2. Fab shop wanted $2500 and 10 weeks to build me a set.
4. We have two dragsters on the floor of my trailer and it was real tight between my headers an the other car's front tire. Lot's of clearance with the Zoomies.
3. Ted from Ted's Fab (sell on Ebay and RJ) was good to work with in getting zoomies special made to clear my F2.