dual 1 ohm soundstream?

A dual 1ohm voice coil sub can be configured as a "single" 2ohm load if the coils are wired in series or a single 1/2ohm load if wired in parallel. Unless one of those amps can handle a 1/2ohm load in mono you will be running @ 2ohm. Without knowing the RMS power output of that brutus amp at 2ohm mono I can't really make a reccomendation but if it is at or less then 900w you should be fine.

I have found that generally you will "percieve" greater bass output to the listening compartment if the sub(s) are aiming back..this has to do with the size the bass wave at low frequencies as it is gernerally larger then the size of most car interiors. You want to be "hit" with the strongest part of the wave for the most percieved output. However, if you have the opportunity it can't hurt to experiment and try it different ways as afterall it is almost impossible to predict what will sound "best" on paper as there are many, many other factors that come into play.

As far as "upwards" vs. "back" I have been told that it is not really the best thing for a sub to be mounted up or down(horizontally) due to the stress of the physical weight and mass that moves during operation. If the sub is mounted normally (vertical) it should extend the life... however I personally have no data to back this up..only what I have heard from others in the industry.

Good Luck

Well regardless the difference between 900w and 1100w is only 200w..really not that much to be concerned about..in other words..it is an acceptable match.

Its not really so much that the gain adj. will compensate for overpower. The purpose of the gain control is there to adjust for impedance mis-match from deck pre-output to amp input. In other words unlike many people think..the gain does not make the amp more powerful per say..if this was the case why would the manufacturers even put a control?

Basically always set the gain properly to prolong the life of the sub(s). Remember it takes TWICE the power to gain 3db of output...and 10 TIMES the power to double the output. So at this level 200w is really diddly of a difference.

Enjoy your system..it should hit impressivly.