Loudness, I doubt anything will be a massive improvement because you dont have room for much variation with your space constraints. However, the W1 does have a slightly higher efficiency and also a lower Fs, so I think you'd see some improvement. Not to mention the overall cleanliness.

I'm pretty sure we have it in stock, but I'd have to make sure if you're interested (today is my day off). If it comes down to it, we could throw the sub in your box and give it a test run.