I dont really see how any of that will effect the sound and ouput lol which will still be bad. But if you dont care and are just doing it for looks then go on right ahead. Just remember it still wont be as durable as a custom built box, throw a strong sub in there and you'll see the box fall to pieces. no matter how much you seal the groves.
If the box works well for you and you want to take the time to change the finish on it then by all means do so. No one can say it's the right or wrong thing to do for you.
yea it really depends on the application. While the vast majority of pre fabricated boxes are tuned high and have limited port area, if the box works well with your intended driver of choice and rigidity is the only factor keeping it from being a suitable box, go for it.