Very nice install, it reminds me of the Viper RT/10 stock enclosure. Obviously yours is nicer looking.
We tried a couple different enclosures in convertibles like (viper rt/10) yours and found that having the sub firing towards the back or bottom makes a lot more bass in the drivers and passenger seat area.
I am sure this enclosure sounds great, but the sub will need to fire into a cavity to create a wave. Without getting into too much detail.
Non the less it looks great and if you are happy with the results it realy doesn't matter what I have done... this is in no way putting down your work. I respect you for what you have done, it looks great. Realy. Just a professional constructive complement.
GOOD JOB.