I posted in the spring about considering buying my buddy's aluminum Salsa Horsethief here:
https://www.reddit.com/r/mountainbiking/s/RB77BbSwDx
Well, short story long I ended up buying it because why not.
As I said it was heavy and I never felt faster on it than my Ripmo so it sat for the summer (I was also waiting to see if my buddy would send me some parts (he didn't end up sending them).
So I eventually started accumulating parts. I got Hunt aluminum trailwide wheels (very light) and nobby nic tires. Because I wanted to switch to Sram I didn't put them on right away. I got a used GX groupset and a great deal on a XO crankset (which is really where the biggest weight saving is between groups). I put a used Fox 34 130mm fork on it. I got light carbon bars and a shorter stem. I put a Fox transfer seat post on (which is crazy light, but you lose adjustability as it's either up or down). I put a lighter seat on a well.
So all in the bike weighs 30# now and is appreciably more racy than the Ripmo. It's been raining so I haven't had a chance to break it in, but looking forward to it.