The cool thing about the Lisa is that you can run LOS on them in a stock configuration (what 95% of the lisas still are) and there are essentially no upgrades that can improve on it because besides from Lisa 7/7 there's no other software for the thing that would demand more in resources. Even maxing the ram makes little sense unless you plan on using the Lisa as an office daily driver which I'm sure every company would hate.
If you are running MacWorks exclusively the various upgrades are now the equivalent of owning a mac 512k and upgrading from there. Extra ram is a bonus. Larger hard drive is a bonus. SCSI allows external peripherals (or even direct booting from), 800K upgrade allows you to use newer floppy-based software. The sound card brings back the standard Macintosh audio functions which the Lisa cannot provide.