The Stryke PR's are able to displace a lot more volume. But with 2, do I really need the extra sweep of the Strykes? Or would I be better off getting the HE15PR's since they are half the price of the Adire PR's? Also, with 2 PR's & a tune of 18hz, how big does the box need to be? I can't seem to model PR's in WinISD & also can't get the LSPCad to download to my computer properly (anybody that can help with this?). Thanks in advance. . . .