I run a 26 cft box and I only have 2 times rise.You can also run larger speaker wire which can help.I currently run 4 guage to my subs and i have noticed a big difference .I have had big box rise in small enclosures and large enclosure.There are alot of factors that can effect box rise.
You need to build it to find out. I have built alot of 6th Order boxes that people said wouldn't work.However,I built them anyways and they sounded great and did pretty good on spl also.every vehicle is different so until you build that exact box in your car you won't know.
I lived in Florida for 26 years.The gulf side is much warmer.the nicest beach is a island off of Sarasota called siesta key.The sand is really white and fine like baby powder.of course you have Daytona beach,Miami beach and key west is nice .