the JL XD amp is a bit more expensive than the arc audio amp. so to keep the entry level system reasonably priced we decided to use the arc amps. the level 2 setup has the JL XD series amps which i have posted for you to see. I dont really expect anyone to go for a level 3 or a level 4 (which i will be installing in my truck) just because of the price point. Level 3 is going to be roughly $5-$7k and the level 4 is more along the lines of $15k. But being an audio shop, i have to have the best in my vehicle for demo purposes.