I have heard the EPIC .18 is a very powerful engine. I can't really say too much about it though, cause I havent read up on it or test it myself. As far as the Sirio .18 goes, no, it's not just an advertising thing that everyone likes it at first cause they think its cool. The sirio .18 is italian made and has the most horsepower of any .18 out there right now (for wat i know anyway). I think they claim that it has 1.7HP. The wasp .18 has somewhere around 1.4-1.5HP (never really told me the exact readings), and the Fantom .18 has around 1.6HP. The difference between the prices of the engines are basically the time taken into making them. A little port and polishing, and any engine can be racing the big bad italians (novarossi, picco, sirio, etc) lol.