Audio research

 Why not borrow the SP9 and listen to it in your system for a few days. That is the only way you will know for sure.

 Preamps have come a long way in the last 30 years, even in the last 10 years. I owned a SP9 in the late 1980s. Most of my later preamps were much better. The Audio Research LS25 mk2 I had was a huge improvement over the SP9. Not to mention my current Ref 5se which is infinitely better.

 If it were me, I would keep the LS3 and buy a separate phono preamp for now. Later I would consider maybe upgrading the LS3 .

 There were a few different versions of the SP9. It should say on the back if it is a mk2 or later. If you email ARC with the serial number, they can tell you what version you have and when it was made. Around 1990 or so ARC stopped putting mounting holes in the face plate.