The pump is different. The smaller Mini's and smaller Double Cones don't use the RD3. The design of the RD3 allows it to create a very linear air to water ratio throughout the power range. The Red Dragon pumps on the smaller Mini's and Double Cones are very similar in their current draw but each has a different volute/impeller combo to insure that the air rate is appropriate to the skimmer body. The caveat is that the Double Cone 130 and Double Cone 150 have an adjustable nozzle that when turned adjusts the air to water ratio. The impeller spins at a set rate but when you open the nozzle up, the air flow increase and the air displaces the amount of water going through the pump. By increasing the airflow via the nozzle, you are decreasing the water flow. On the smaller Double Cones, you use that adjustment to tune the skimmer. The Mini's are more set it and forget it. With the large double cones and Mini 200 that have the RD3, you use the pumps speed controller to fine tune the skimmer. As you decrease the speed, you decrease the wattage as opposed to the AC blocks that spin at one speed.
That said, don't discount the Mini 160. It's still a great skimmer and if you have a reasonably decent fish load and regular feedings, it would work fine. On the flip side, there is nothing wrong with the Mini 130 or the Mini 150 for that matter. They just require more tinkering with the nozzle to get them fine tuned for the load. The sweet spot for the nozzle setting is usually between 3.5 and 5 turns out depending on the load, sump depth, water tension in the sump, salinity etc. A fraction of a turn can make a big difference so it takes some time to get them dialed in but they work wonderfully well once you find the sweet spot for your setup.