I have just started looking into doing it, looking around here its difficult to find solid info on these models. For me at least. New to the forum. I would like something a little more lively, the 4.0 feels really saggy, and i do not like that at all. It is an 07 Enduro Elite. I have seen where some people have remote'd their reservoirs. Im not sure what all will go into that however. If you say that it makes a world of difference and the coil is the way to go I will probably go that route. I live in TN and not the mountainous part either, Memphis, so Im in need of something that will soak up the big hits but not sag like my grandmothers breasts.
Mines an 07 elite as well. I blew the original 4.0 air three times, and that was before i even started riding at the bike parks! If you have any questions, feel free to hit me up, my enduro is not stock at all!
Had my mechanic at my local bike shop do it about two years ago. Upgraded from the fox DHX 4.0 air to a Fox van RC coil. Old shock length was 8.5 x 2.25, however since they do not have a coil shock available in the 8.5 x 2.25, my mechanic measured it out and checked and we were able to make the 8.5 x 2.5 shock fit in the movement of the rear suspension safely. I wanted a DXH RC4 coil but the shock reservoir was right up against the seat tube and you wouldn't be able to use one of the adjustments so I had to go with the Van RC.
What year/model is your enduro and what shock were you looking at getting? You may be limited like I was with choice due to bigger reservoirs on the more advanced shocks. I must say though, it's a world of difference putting the coil onto this bike, soaks up more bumps, bigger drops much easier and the suspension feels lot more progressive. I wouldn't go back! Only thing I've noticed is that once the nitrogen charge wears low and needs refilling, you will definitely feel the lack of a full charge in there, service it and it feels amazing again!