I run a BLTouch on my taz6. BLTouch alone is a huge upgrade for the taz in particular, as the build plate is quite large, which amplifies bed tilt. The bl also enables mesh leveling, which is also valuable due to heat warping of the large built plate. My taz runs a quick mesh bed level at the start of every print, and also uses the BLTouch for initial z leveling as well. This means my nozzle no longer gets used as battering ram. (Seriously, your nozzle shouldn’t touch anything but hot plastic IMO.) This process has worked flawlessly for me and made the printer a true print-and-forget workhorse.
Magnetic bed is another huge upgrade. I run one from printed solid, which was inexpensive and has been a great upgrade. Huge ROI on this.
I will upgrade the taz to something with tmcs at some point, but I run kipper on all my printers atm, which is almost like a software-powered hardware upgrade. It’s a great way to increase performance that also has a noticeable impact on printer noise. It won’t make it silent, but it does quiet the printer overall.
I used to run octoprint with kipper, but recently switched all my printers to use moonraker with the fluidd UI. This is printer control server and a (beautiful) web app front end built for kipper that allows you to control everything on a printer from any browser (right down to configuring gcode macros, firmware settings, etc). With this upgrade I really don’t use the screens on any of my printers much at all, as I just manage everything from my phone/tablet/laptop at this point.
Finally, I swapped out my original taz6 tool head for a custom design based on the lulzbot m175. This change really increased overall print quality, printing consistency and viable printing speed much more than I would have expected. Huge and worthwhile upgrade from the original hot end.
Ok, really finally. Check out some of @piercet s mods. I did his frame upgrade and belt adjustment upgrades. Both worthwhile adds.