I made a similar box for a customer about a year ago, in a CRX Del Sol. The fibreglass work looks pretty good mate, I tailor my boxes to suit each individual sub's capabilities and specs, but the cubic capacity of your's looks similar to that of a standard generic 10" MDF box so your laughing as 90% of subs will sound fine in it.
i'd personally sell them carpeted, it would cost an extra tenner to trim and improve the finish no end