Re:
I transferred the internals from a SID Race fork into, I think, a Dual Air as the upper legs of the Race fork were severely worn. The lower legs and upper legs of Dual Air are the same except for Race fork's aluminium steerer so all fits OK.
Did this several years ago, 10+, so my memory of what other tools I used might be wrong. I think the only special tool I required apart from the usual tools I have for working on my cars or bikes was the one to unscrew the baseplates on upper legs. I used a big nut that I drilled out to remove the it's threads, and a bit of a file to clean up any sharp edges, as it has to slide over damper rod to fit in hexagonal recess in baseplate.
A few links to other info in this thread,
https://www.huckingkitty.com/forums/vie ... f=11&t=164
This one from above thread,
http://www.birota.ru/manuals/rockshox/s ... eGuide.pdf
says that the nut I used to make special tool was 15mm. Also says baseplate is a left-hand thread, see "Removing Dual Air Assembly" on page 3. The left-hand thread info I didn't remember but one of the posters on above thread seems to not have known and damaged baseplate threads by trying to remove in wrong direction.
Hope this helps, think my SID Race forks may have been older than the ones in links above but appear to have similar internals. The Birotta site is where I think I got my info from to do this years ago, there were lots of PDFs of various manuals on there.