Need some build advice...

So I have plotted this with THIS driver. After playing around with enclosure sizes and what not I have a good response from it. But at 25W well under the 60W nominal from Tangband the predicted cone excursion is quite worrying at 10Hz. But is this much to worry about is there that much 10Hzness in metal/rock? I doubt it?

The thing is compared to my speakers which need 25W to reach 94.5dB SPL which is well enough where as the ones I have plotted only need 6W. So I don't think I need to worry?

Here's the plots...




What do you think?