Here I put the details as I replied to one of the members
I think it can be useful:

Hey,don't buy used stuff,pointless waste of monetary resources.
If you aren't hesitating to drill the cluster I would say,go ahead with this DIY,it took me about 3 hours the first time to get it drilled and split,but it was about a year ago and I haven't had the new ribbon cable available,so I just pulled the old ribbon cable and cleaned a bit,got it all together with some extra pressure bands of folded slices of printer paper.Could restore the mileage characters and was pretty happy about it.
So yesterday,I've got all the components together and said no more guessing because of dead pixels and took everything apart,it took me about 2 1/2 hours to get it installed in the dash.
My fears were about messing up the pins(if I can call them so) on the printed board or glass conductors on the LCD connector.
Everything went smooth,but first time I was fool and didn't put the "pressure bands" and I didn't get all the pixels back, when I checked it connected.
Second attempt was successful.For around $60 bucks shipped I restored and improved the look of my cluster,not $1000 bucks from dealer.
The hardest part besides drilling is not to mess the gauges. Since you have to lay it down on that side,so some support is required so they don't get pressed into the motors,otherwise you'll get an abrupt speedo or tachometer or both,not nice,I have my speedo getting stuck since the first time,but I could get it better this time,so it's reversible to operative conditions IMO.
Also,the board(green) is pretty tough to get it remover from the black back housing,since you don't want to break anything you'll try to be careful and there's where the point of balanced force is coming into play.Slowly pry it with some flat anything,but don't poke to deep..it's got a lot of fragile chips and stuff,so be reasonable doing it.
Once you have the board out and unscrewed the the white block through the drilled holes you'll remove it,be advised that back light pins are sitting tight in the board,so apply moderate strength.Once removed pull the old ribbon away and throw to the garbage,since it's the shame of German engineering.
Clean the leads with fine grid sandpaper and gently remove the crap out of the board,clean with some contact cleaner and do the same with the LCD glass,I used the bamboo tooth pick,pretty stiff one,but be careful and don't scratch the glass,you'll see the glass "leads" and they are fragile looking ones.Don't be scared,just extra caution!
So..to align the ribbon cable(put the rough side of the ribbon on the board's leads) ...on the green board you'll see the leads through the ribbon just once aligned put some clear scotch tape to hold it in place,I used 4 pieces between every screw.once done place the white box and put it in place so back light pins get into the board ,but leave some clearance and squeeze 4 folded paper pressure bands(or a thin cardboard) so it makes contact with the part of the ribbon that contacts the leads.
Now make sure the other end of the ribbon is sticking out on the other side and tighten the screws.
Take the LCD glass and where it make contact with the ribbon you'll see(under certain angle and light and middle strip which aligns with the same on the LCD,and it's pretty easy since you don't need to hold the cable anymore,just lay the LCD onto it and align and put the black metal holder that snaps on top of LCD,but leave a clearance to squeeze in the tiny folded pressure paper make sure it can't be seen from under the metal holder ,Snap in place.
At this point you'll need to reconnect the cluster the way it is,so you can check if everything is working the way it should,I assume it does,and now put the black back housing on ,screw the torx screws and prepare the rings.
To put the rings in I would you'll need to slightly press on the sides so you can pass it through the gauge holes,gently,it will pass through,just keep in mind the inclination of the clear plastic ,so the top part goes first.Snap the ring and repeat with the rest.
No soldering of any king is required.
Put it all together and enjoy YOUR cluster and all the info it provides,the way it meant to be.

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e53 '00 4.4i Oxford Green II Freshly rebuilt tranny(2nd one) and transfer case/front shaft
e70 '08 3.0si Sapphire Black cinnamon leather 7 seats
e61 '06 530XI Sports Touring Silver - SOLD