Fitted mine (springs only) just after the 1,000km service. Was noticeably stiffer, raised the rear 63mm and the front 67mm. Just clocked over 3,000km and height is still the same.
The springs are the same free length as the stock springs, so no additional travel is possible. I also noticed that I only had to drop the diff about 30mm past the full shock extension to drop the springs out, so do not put longer shocks in unless you are using something to hold the spring from falling out at full travel. Could be a little bit of a problem otherwise
Over all after settling in for a few weeks the ride is great, just a little stiffer than stock which is perfect for the additional height as you dont get anymore bodyroll on corners. If I drop the tyre pressure to about 32psi, the ride is the same as it was with stock springs on 35psi (as it was delivered).
Harass your dealer for a good price too - got mine real cheap
Heres the post I did when I put mine in