IMO the baddest .28 motor on the market is an EB Modded Novarossi 528 XR. I have two of these monsters and they are awsome. They are a bit spendy arount $400.00 modded and around $320.00 stock. The stock version will probably blow most other motors away. The PICO .28 is also good especially if you are looking at a bit more resonable of a price (around $200.00).