How difficult is it to install one of these? Any write-ups out there that can help guide me through this?

Well I just found the quaife install writeup from 98sr20ve. I guess that should apply to this as well. Is that really all I need to install the nismo unit though? Do I need to change any seals or bearings? I'm asking this because I noticed an LSD install kit on the sr20dev website: $255 Install Kit for LSD (Bearings, Speedo Gear, Etc...). I didn't see any of that on 98sr20ve's writeup.

I'm glad you found Steve's write-up. Search for 'nismo lsd install' and you should find a post by me on the lsd for non-lsd trannies. The install for lsd trannies will be the same, but some of the part numbers could be a little different.

jacen99SE,
I found your post and you wrote you needed these parts:
38440-D2100 (you need 2) bearing
38431-D2100 Speedo stopper
32701-D2100 SPeedo drive gear
Will I still need to buy these parts if I am just transfering the LSD from one broken tranny to another tranny?

Also 98sr20ve wrote this in his writeup:
4. Three bolts hold in the shifter mechanism and three more hold the gears in. Remove all 3 and remove the gears, paying special attention to how they all go in.

I'm having a little trouble here. Do I remove the 3 shifter bolts and the 3 gear bolts (6 bolts) or just the 3 gear bolts. I'm having a hard time getting to the third gear bolt because it's inbetween some gears.

jacen99SE,
I found your post and you wrote you needed these parts:
38440-D2100 (you need 2) bearing
38431-D2100 Speedo stopper
32701-D2100 SPeedo drive gear
Will I still need to buy these parts if I am just transfering the LSD from one broken tranny to another tranny?

Also 98sr20ve wrote this in his writeup:
4. Three bolts hold in the shifter mechanism and three more hold the gears in. Remove all 3 and remove the gears, paying special attention to how they all go in.

I'm having a little trouble here. Do I remove the 3 shifter bolts and the 3 gear bolts (6 bolts) or just the 3 gear bolts. I'm having a hard time getting to the third gear bolt because it's inbetween some gears.

If the used NISMO LSD already was installed and working, you do not need to replace those parts unless they seem bad.

You want to remove all 6 bolts. I had to go back and look at some of the pictures I took and some of the pictures steve provided to remember that. Also, play close attention to the way the small gear by itself is installed.