Sound system upgrades

[Alberto Aguirre]

My truck (RST z71, Crew) came with the plastic cargo organizer under the back seat. Part of me wants to keep the storage it provides but it’s preventing me from getting a subwoofer under there. 
Any boxes out there or set ups to save storage space and get a sub??

Also, shop quoted me at 1700 for Alpine type R 6.5in comp (front) and coaxial (in the back), 5 channel amp by JL, JL 8inch sub with enclosure,lc7 converter and labor. 
I think it’s a fair deal. Opinions??