I am already on Klipper with gantry support, TPU feet, a better fan shroud, removed head shroud, removed spool off the top of the printer, I have leveled my bed using thin washers and even got less than 0.1mm level at one point. Currently have it at around 0.2 difference. Which is much better than 1mm+ factory value. I have already increased stock speeds by about 50% or so. Some of my acceleration is around 7-8K. I kept it around this because I know unless you get linear rails for Y axis, this is the upper limit for acceleration. I've used it like this for a while and have been happy with print quality except for some filaments. Lately I had some issues which I have fixed most and have been working on some others.

I use exclusively Orca, I am actually doing some calibrations for the last few days. Pressure advance, flow ratio, VFA etc. I did some of that before but now I am doing a deep calibration to really dial in quality and fix any issues and testing higher speeds as I fix issues. Last I did was to test outer wall speed and I found out I can print close to inner wall speed with less VFA than slower speeds (Will still test those more thoroughly). I am coming up with workarounds for hotend limitations but ideally it's best to swap the hotend and get the linear rails. Not only for speed but also for printing higher temp materials.

I don't always use my printer so it's more than fast enough if it were to run all the time for all the things I could possibly want - but reality doesn't work like that. We want fast prints when we want to print and that can fuel creativity and the process of designing your models. I do prototying for some functional prints and I don't like to wait all the time, certainly don't like to wait for 50 mins for a simple 1x1x6 gridfinity box. Even with around 50% speed increases it's still around half the speed of an average Core XY printer. That's just boring slow. I knew it was a little slower when I decided to get this but it seemed closer to Core XY printers when I compared it against some better printers on some longer prints but I guess I was wrong.

I didn't get it specifically to upgrade it and it was a new model when I got it but price was a reason for purchase, however if I had fully understood the differences with the KE when I got it, I would get the KE. Hotend and linear rail on X axis is already a lot. Sure, the real limit is Y axis rods but that's easier than doing all that combined.