Soundstream Continuum xover or passive?

First off you should be using both the passive crossovers that come with the speakers and the crossover on the amp, or the one on the deck. The crossover that comes with the speakers divides the signal up between the drivers and the tweeters, sending the high frequencies to the tweeters and the rest to the driver. Now buy utilizing either the crossover on the amp or the deck you can specify at what point the signal starts being sent to the speakers. Ex ample 50 hz and up or 80 hz and up or 67 hz and up or whatever. This prevents the ultra low bass being sent to the speakers that cant produce the sound and causes them to distort, also since the subs will be picking up this low end signal there is no reason to waste power trying to get the front speakers to play it anyways. Same goes for the back. As far as using the amp or the deck goes, the amp crossover is probally more presise then the deck so I would probally use that one however if you use the deck crossover than you can change it on the fly so its really up to you, but I would use the amp. Now on to the power question. Soundstream amps in the past have had pretty conservitive ratings on the output power so I would think that it would be sufficent. The subs could handle more but they should run perfectly fine off what you have. i hope this helped some.double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer