Hi. Your advice re strut brace for a Spider was very helpful. Ditto springs/dampers. Eibach has a great reputation so that sorts the spring upgrade. Would you pair them with Koni or Bilstein dampers, or are they equally good? Thanks in advance.
I went with Bilstein B8s to go with the Eibach kit and Powerflex bushes. I'm pretty with it except that the steering needs a little tweaking - possibly less castor - so that it doesn't follow cambers, especially to the left, as much.
You get varying opinions and I haven't tried the Konis, but no other high end damper company uses the Koni hydraulic design any more. The 159 is quite heavy and a monotube gas damper design allows a large piston to provide large damping forces, which is useful for high speed swerving. I don't know how the Konis compare on this, but I'd go for a monotube gas damper over a twin-tube gas damper (e.g. KW coilovers) for this reason. I ordered mine from Alfisti.net and they got to Australia in about two weeks.
If you lower your Spider then you'll want to consider the Powerflex bushes too. The front suspension geometry is not adjustable and lowering it will significantly increase the negative camber on the front wheels. The Powerflex upper arm bushes have an eccentric mount design that allows the camber to be adjusted to reduce the likelihood of you wearing out the insides of your front tyres.
Even if you don't get the lowered springs, it is worth considering the PU lower suspension arm bush as the standard rubber ones tend to break down and make a mess of your alignment.
My suspension guy - Chris at In-Line in Queanbeyan, who does all the local Porsches - initially recommended just the lower bushes to look after the tyres. As Mozella suggests, the stiffer upper bushes may be too far many drivers, but he wasn't aware that the Powerflex adjustable bushes were available for the 159. He did point out that lowering the car would increase inside shoulder wear and looked for a camber adjustment kit (e.g. K-Mac) but then I pointed out the Powerflex ones were available and we went with these.
To do it all properly you'll need to replace the suspension top mounts as well, with about a day in the suspension shop (at independent Porsche rates ~$1000), plus you should take your car back for a realignment once everything has settled. So think of $3k all up. I changed mine once I'd done 100,000 km as that's a reasonable life for standard dampers.