If you have a Bilstein B12 kit, for a SW, I'd make up some spacers for the bottom of the rear springs to raise them 15mm from the strut spring perch. I think simply making spacers from a fibreglass paste should be strong enough. Just make a few drainage channels in the bottom. That should sort the aerodynamic angle of attack.
As the SW is heavier at the rear, use the holes for the rear ARB closer to the bushes. The JTD has more weight at the front so won't be significantly different from the V6. (the V6 is heavier overall but the JTD has a greater forward weight bias). The handling should be balanced at that as the variable rate rear coil springs should effectively self adjust the handling. As with any kit, the greater the roll angle, the greater the understeer effect. Therefore, if the rear is too loose in the wet or greasy roads, fit the rear ARB links to the outer holes.
So in your opinion i could stick with the Eibach ARB and just change from the softest to hardest setting according to driving conditions? I will have to change the front ARB for sure because mine got bent in a very hard pot-hole. We've take some time to find out what is making the front lean more to the left side than the right side, till the moment i've got the idea to unlink the ARB to see if the height gets leveled. And... surprise, it gets fully leveled, linked the droplinks again and it got uneven. So i will have to change it. Considering the labour cost i find out that is a good idea to make the upgrade of course with front and rear to keep everything balanced.
I have another concern that is the Xenon headlight leveling pieces. Hope the new ARB doesnt mess with those.
Raising the rear end seems a great idea.
The other issue with the Eibach ARB is that some guys seem to lose grip in tight corners. The thing is... how tight are those corners...? I love to do some twisties. My concerns is that i end up with a FWD car that gets much less progressive in terms of throttle control during corners.
Thank you for your input