I've been keeping an eye on this thread as I've had a pair of boxes for years and never did anything with them.
Last night I ordered a pair of Polk Audio MW 5530, they're discontinued apparently but there's a few sets still on eBay. With similar specs and reviews to the Tang Bands they should be a good option. Also they're cheaper, and fit within the stock housings with no cutting required apparently.
What amp and head unit are you planning to run Nik?