Number 1: Don't stick your subs in a pre manufactured bandpass box unless it's either custom made, or was made by JL. It will sound like sh!t
Number 2: That symmetry is not reallly the best piece on the market. It may be fun to play with a $200, but there are some downfalls. You first need to find out if it's the Symmetry or the Symmetry 2, they are slightly different. There are a few problems iwth the symmetry 2 that I know of:
1. They tend to develop a bit of hiss to them and must be sent back to RF for a fix. This affects some units
2. The crossover locations are not continuously variable. They are very limited in fact, and may cause you some problems.
3. The crossover slopes are fixed at -12 dB/octave. For a high end processor, that's pretty shallow. I'd like to see at least the ability for 24, or 36 dB's.
Also, you need to find out what EQ card in in there. It has two add on cards that you needed to purchase separately in order to make it an EQ. There was a 14 and 28 band card...they are still over $100-200 used on ebay.