The Thiele-Small parameters for those two drivers are not equal. Obviously, by just looking at the two drivers, you can tell FS, VAS/CMS, VD, MMS, XMAX/XLIM and SD are not equal...LOL! smile

I'd be very careful if I were you. If you replace the old driver with the new one, you might alter the flux quantization within the magnetic gap and cause your entire house to get sucked into never-never land smile.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated