FWIW, in the last few days I dropped in new drivers and radiators in a pair of eighteen year old Klipsch, SW12 II boxes. The replacement drivers and radiators were purchased from Parts-Express. They're doing just fine as they're now playing in the background with the intent of getting some loosening up time on them (fifty hours worth) before dialing them in.
Personally, just for the education one receives by fully exploring a home exercise lab of this type, I say buy a replacement eight inch driver and drop it in. For the education alone, it's well worth the price of admission.My recommendation, go with the good stuff.
Explore the "THIELE-SMALL PARAMETERS" (T-S parameters) and what they all mean. Check out some online box size calculators. Explore what the cone is made of, what the differences are and what the benefits are. Explore magnets and how magnet sizes play into the overall operational equation. Explore box sizes, manufacturing materials/thicknesses, ported vs sealed vs passive radiator, linings/insulation and how changing the box size changes the performance characteristics. It's a hobby, have some fun figuring it all out.
-Edited by BeeMan458 - 1/19/13 at 8:50am