Currently running 2 SA 15's, thinking about switching to a X 18

[hispls]

Are C pillar walls worth it,

Oh yes. I would say if you have a pair of 15's in 6 cubes you probably don't even have room for a pair of 15's much less 4. Whatever you do, don't skimp out on box volume or port size would be my advice.

[GassenD]

I'm going to do some measuring tomorrow, my current box is 10 cuft gross, and double baffled (All the way around).. Plus once I move my battery and amp from behind my back seats I'll have some more room..

So i'd probably have to just double baffle the top piece, make some bracing inside, areo port, and maybe even invert the subs to squeeze every little bit I can..

[DylanBunch]

I wouldn't wall unless at the b pillar. Wasnt impressed at my c pillar wall (then again it was shit)

[notorious97200]

Port tuning is too high for the lows !!! 37 Hz !

Try a lower tune on your current box : a longer port will reduce box volume. But it could be easy to do, and provides very good results.