My guess is the weight difference would change the spring rates.

Yup, agree!

Sometimes the aftermarket doesnt tune that precisely though, and spec the same parts across the range.

I see this often with Bilstein shocks.

Btw, a bit of research seems to indicate Sachs makes the struts for the Eibach range. They are OEM of the factory sport struts (at least on mine). So these look to be pedigreed parts for a really nice price!

I would be concerned about getting camber in spec after though, as these are also a lowering kit.

The fronts have inexpensive solutions via strut to hub eccentric bolts.

The rears are another matter, as the only camber solutions I have seen so far are Kmac lower arm eccentric bushings that cost more than the whole Eibach suspension kit lol!

30mm lowering shouldn't add too much neg camber. Just min out the adjustments and you should be able to keep it in spec. I dialed out a ton (2 deg iirc) of negative camber on mine when I did the rear suspension refresh just by using the adjusting bolt...

You can always add a very thick spring pad in the rear (and front, for that matter) to take some of the drop out of the kit.

Used to use the different thicknesses to tune a "stock class" suspension when the rules didn't allow for adjusters. You can shift an amazing amount of weight with 5mm of spring pad when you are corner balancing. ;)

Thanks for the input. I guess the biggest question is if the mounting positions are the same between the 3.0 & 4.4?

Ranger, thanks for the heads up on the pads. I didnt even think of that, I thought BMW didnt use variable thickness pads. I do know Mercedes does, which I used to balance out rake and get as low as possible on my old W124.

I am maxed out on rear camber now with around 1.8 deg, having replaced just the upper control arms. I may have to replace the lower bushes to get within spec on a lowered suspension.

C, yes, the suspension layout and mounting points are identical for all E53 chassis vehicles over its entire production.

I just ordered the Eibach kit. I'll update after installed.

Cool! Very interested to see how it compares to the OE sport suspension!

So as it turn out, it was too good to be true. The deal was only for the coils and no dampers. Oh well, back to the drawing board. My X does have the air bags on the rear so trying to decide on wether or not to keep them or convert them.

Wow that sucks!

I thought you had coils all around. That narrows your options somewhat without converting.

OE non-sport shocks/springs/bags are all I can think of at the moment.

Poo. False advertising/careless internet catalogs annoy me greatly.