I found the thread I referenced earlier.
It was about the Phantomm upgrade, which I was very sceptical of.
It deals exactly with what you want to do.
This post in particular may be interesting: (Old) Lead Screw Upgrade Kit (OLD THREAD)
I suggest you read up, there’s some good arguments in there from both sides.
I myself remain sceptical about using an 8mm acme on anything over 500mm of span, but the reviews of the Phantomm upgrade were mostly positive as far as I can remember, so what do I know. 
Good luck!
btw, there’s a setting to change whenever you change your drive system. I don’t use an arduino anymore so I forgot which setting that was but I’m sure someone can chip in about that.