The MB Quarts are in but yet to be installed, hopefully it'll warm up a bit and we won't get another 4" of snow

!
I've debated back and forth on the sub and basically I think the dual 8" setup will simply sacrifice too much trunk space. Holiday travelling seem to confirm this.
Therefore, is the single ScanSpeak 21W/5555A
still the optimum option? I guess on the one hand it sucks to spend $160 for one speaker when it would buy two, but I am getting a quality piece it seems. I also plan on getting the US Acoustics 6300 50x6 if it is still the bargain amp.
Thanks again for all the input you guys, hopefull this SVT will be rockin' soon.