Since the EZ advances the injection timing, most people report more combustion "rattle" with the EZ. Mine was somewhat noisier with the stock injectors. It's really noisier with the DD2's. Frankly, I'm thinking about springing for a TTPM to get the fueling without such aggressive timing - especially since we tow heavy (21,180 GCW/21,500 GCWR) with an HO.
Rusty