Hey there you vintage quadiophiles! I know- this topic has been kicked around until the diamond fell off the Shibata but I'd really like your collective input on my question/situation here in the land of old school quad. My setup is a Sansui FR 5080S TT into the QRX 9001 (fully restored by QRX Resto) using low capacitance phono cables. My current cartridge/stylus is an AT14SA bought as NOS a few years ago and used approximately 100 hours. I get a nice strong CD-4 radar signal every time on the QRX and my CD-4 records all sound very nice, with clear discrete 4 channel separation on my records, which are generally VF+ to NM- However, always wanting to improve things, I'd like to upgrade the cartridge to either the AT440MLB ( discontinued I know, but which can buy as NOS) or the newer AT VM750SH. I really love AT products so I'd like your opinions as to whether it is worth it to upgrade, and also, especially, how much a PITA it is to use the mounting screws upside down when trying to align things! Thanks so much for your input. Stay safe out there.