I'll explain further //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
I have them both sitting here in my shop -- bought a pair of 1508s to measure TS specs on. They have a very similar voice coil size but the SA-8 has a stronger cone, bit stiffer spider with more usable throw, a plastic triple joint re-enforcement ring, and IMO better voice coil cooling.
So... again... if a DD 1508 will handle it then the SA-8 would drop right in and handle the same thing if not more.