Nothing wrong with soundstream. Better than Power Acoustic, Kove, Boss, toss up between Hifonics (depending on what series). The XX and XXV series Hifonics are hard to beat. But somewhat hard to find.
If your only trying to get louder than your friends. 1 soundstream and 2 of the SX's will do that and save you $$$. Your going to have to put $500 to $1000 in your electrical system alone to support 4000 wrms. But if its not a problem go for it. It will be stupid loud.