@Phaedrux
Thank you for all the good advice!
I will definitly wait with the dual z upgrade and see how the print quality changes with the better extruder and control board (Duet and Hemera have just been ordered). The added weight of the direct extruder might make it worthwhile, but i will not jump to conclusions before actually trying it.

That Guide is, as always, very helpful, but since i used the ender 3 for about a year before getting the tevo little monster, I tweaked quite a lot
I added a BL-Touch first and got a MKS board with 2208 drivers. I used capricorn tubing and new couplers for the stock hotend and extruder (the couplers helped a lot more than the tubing i guess... ) and swapped the hotend fan to a noctua with a buck converter.
As a part cooling fan i used a 6000 rpm 5015 12v sunon fan which is actually pretty nice, but does not like to be run with less than 12v and i can't figure out how to control the speed on it...
I also have a 92mm noctua fan for the PSU (with a PLA-Cover instead of the metal one... feels sketchy) and one 80mm fan for the electronics.
Basically I only hear rattling when small infill patterns are printed and the part cooling fan.

I just really want to get rid of all the converters and might swap all the fans to 5V ones once the Duet is here. Controlling the part cooling fan a little bit more granually than "on and off"would be nice...

Tanks for the Tipp with the ender 3 pro PSU. I could get that for about 35€. The passive Meanwell ones i could get from reputible sources in Germany are about 150€; The ones with temperature controlled fans are about 90€. I will look into that a bit more; I dont really know if i can trust Brand-Stickers from chinese vendors

@droftarts
I Will definitly look into that! I was kind of scared that the two Z-Motors might bend the gantry, but the documentation states that i could adjust the maximum correction value for each leadscrew, so that should not be a problem! Thanks a lot! I'll be aiming for about 60mm/s print speed and 150mm/s travel, so the motors wont really matter i guess... (i have a 24v power supply already. the cheap one that came with the printer... If you know a "safer" option with about 350 Watts and a silent fan, I'd be happy to upgrade that fire hazard as well)

@Phaedrux
I know what you mean... I've thought about "just getting a Prusa" a lot, but 3D-printing is more of a project/hobby for me, not a tool, so spending dumb amounts to not see a huge improvement is kinda fine...
anyways: I've been looking to upgrade to a direct drive for a long time and the hemera seems just perfect! It does not require huge modifications and should work just as good as a bondtech/V6 combo (which would cost a lot more) and should come with a 0.9° stepper (although it's not stated in the datasheet)
I live in germany, so the prices for a Duet-Wifi and a Hemera add up to about 300€. The metal piece i need for the dual z conversion costs about 4€ (a leadscrew, brass nut and coupling add up to about another 20€), so even if it does not help much, the cost does not really matter after spending 300€ on important stuff...
btw: new steppers for the machine would cost about 60€. I don't need a panel due (which would cost about 100 €).

I've read your guide and really like it:) It's part of why i thought upgrading the Ender 3 until it's no longer a creality machine but rather my very own machine seemed plausible

I might just go ahead with the Duet and Hemera stuff and look at the prints before upgrading any of the mechanics (other than the lead screw with 2mm pitch which i ordered for 10€ jesterday after reading you comment).

Thanks a lot guys!

EDIT:

well... nominal steps/mm is 409 and if The titan documentaion is correct (which i assume), that means it's a 1.8° stepper with a similar gear reduction. That should still be fine though @Phaedrux , right? It's half the resolution of their titan extruder. I don't get why they would do that

Hey guys,
I've had a duet wifi on my Tevo Little Monster for about 6 months now, and although the print quality is not outstanding due to several mechanical problems, I've never really gone back to using my Ender 3 with it's MKS board and Octoprint ( The Duet board is just so much nicer to work with).

Since Christmas is coming I wanted to treat myself to some Upgrades to my Ender and need some advice on a couple of parts. Currently I'm planning on upgrading to this:

1)Duet Wifi - obviously
- I want to keep by BLTouch - should work fine
2)0.9 deg. Steppers
- Possibly with some cheap Dual Z-Axis kit and two stepper motors for Z
3)E3D Hemera
4)Hiwin-Rails for Y und X (If i feel like spending another 200 bucks...)

My main question is: Would the E3D High torque axis motors be a good choice? On paper they seem to be better than the 17HM19-2004S ones recommended by dc42, plus they are all black and have plugs instead of wires coming out of them...
Stepper motors are confusing enough and reading the wiki and comparing the motors made it kind of worse I always assumed "they just work. 0.9 is better than 1.8 and longer motors are stronger! The DuetWifi can drive any Nema17, so you are fine with most of the stuff you find online"
A little insight or someone more qualified than me saying "both are fine" would be a massive help for me

Secondly the Dual Z idea seems a little challenging:
When using mesh bed levelling, is there a benefit to not wiring the two steppers in series? (connecting one of them to the spare extruder driver and using software to level the gantry)
It seems like this could reduce the z-movement during a layer with an unleveled bed, but is that even noticable?

I hope you guys can give me some insight. I like tinkering but i might not be very good at it If you want to i can update you on my progress