What I've been noticing is that you will have to have longer control arms, tie rods, and tc rods. Then you will have to use a maxima ball joint or something comparable to get the angle of the spindle correct. This is all I've been reading. Too many people just try and do it the easy way and realize that they can not get correct camber. Most of them end up with positive camber by the end of it. If anything you want negative so you can have some adjustability there. Why else would you want to upgrade to coilovers if you can not use the full range of them?
Just what I've been reading over the last couple of weeks.
I've kind of given up on it and am thinking about using some z31 hubs to convert over onto our spindles and weld in some threaded sleeves for the coilovers to thread down into. There's a guy in the vendor forum that builds them for the s30's and am trying to get him to sell just the fronts to the s130 guys. http://www.zccjdm.com/
Check it out and read more into if you would like and decide for yourself which is the better way to go for your application.
Thanks,
Lindsey