I have heard from people ont his site that koni struts require "extensive modification" to work on a 240z. I have never heard anyone explain what this means? Summit racing now sells Koni adjustables for the 240z. I ahve seen web sites claiming little difficulty in doing this upgrade. Can someone explain this to me? I'm just curious.

As always, the answer is: "It depends..."

Which Koni shocks?

If you are going with the racing Koni 8610-1437 or 8611-1259 then you should shorten the struts (although you don't have to).

summit says part number 861812 (rear) 861811 (front)

They are Koni Sport Adjustables.

Those two are the standard Koni red inserts, that can only be adjusted while they are out of the strut housing. But they should fit fine without modifications. Although I haven't installed a set myself yet, so I can't confirm that.

Has anybody experience with the Koni red inserts? The price on ebay seems reasonable ($150 per pair). If I understand this correctly, the Koni inserts will not raise the standard height of the vehicle.

And if you have, how is the ride and what setting did you use? As Arne mentioned and from my review of the Koni instalation guide, the shocks need to be adjusted prior to installation.

i have got 861812 (rear) 861811 (front) in my 260z, they require a bit of modification to get them to fit in a 260z, although i dont really know what as i didn't do it.

the ride is heaps better than stock, although i haven't driven any zed besides mine so no real idea sorry. they are being used with low king springs and have dropped me car to the height i reakon they should leave the factory at (ie, it could still be lower, but it doesn't look stupidly high)

i had them installed by toperformance here in australia, and the put them on the settings they belive are best (not sure what they actually are). it feels alot more stable, however the front still feels like its floating a bit sometimes, but then its currently pretty hard for daily driving, but not to bad.

but then i bought most of my setup off a guy who had just upgraded to coilovers as he wasn't happy with the setup at all. he had adjustable sway bars and said no matter what setting any of it was on, the car would just slide in the wet and never felt right, so ? he's a member here so might chip in