Simply replacing drivers with something random that fits will not get you the results you want. If you could get Polk to tell you the Thiele-Small parameters of the woofers, you could then buy something that's close and get satisfactory results for garage use. Otherwise, it's a shot in the dark.
Replacement Woofer for Polk TSI 100
Got a pair of these with dead woofers. Polk wants a bunch for new five and a quarter inch replacements. Whats a good place to look for a replacement woofer for this little speaker that will be used in the garage if I can fix them.