jpitman2

Because I had M474 (Sport Suspension with Bilsteins) from new I already had the correct springs, so there was no need to replace them. Despite the book specifying tyre pressures of 36F 44R (without regard to suspension) I have found 38 to 40psi on all 4 corners to be more comfortable, and still handle well, at least for my driving style - fast is good, but not agressively so. The book does note that different front springs were not necessary when adjustable height front shocks were fitted - note that the base of the force range is the same for both types of springs, the only difference is the length. If you get adjustable Bilsteins, and set the height to spec F & R, you should be fine.
jp 83 Euro S AT 57k

guznax

Thanks for your clear explanation!
This certainly helps! Bilsteins with stock springs are a serious option for us.

drnick

Speedtoys

Debatable...considering there is no balance between compression rebound available, so it will always be too stiff one way OR the other, and that it's a mountain of a b***h to adjust...

And considering the platform, why even bother. It's a GT, not a 911.

And..as such, I have a set of Koni adjustables with only 17k miles on them for sale, I installed new Boge's and the car was to me, instantly better.

SeanR

I much prefer the Koni's (adjustable) over Bilstiens or Boge's.

jpitman2

Are these Konis you speak of adjustable installed, or do they need to be removed to do it ? To the OP - I suggest you get a ride in cars similar to your model , one with Bilsteins, one with Konis. I dont know about Konis, but Bilsteins are rebuildable - local agent here in Oz did my rears for ~ 25% cost of new units IIRC.
jp 83 Euro S AT 57k

SwayBar

Just another data point/opinion:

A racer-friend has adjustable Koni's on their GT and thinks they are way too stiff to the point of fearing damage to the computers when on a rough stretch of road/hwy.

I think the stock Boge/springs, 18" wheels, on my S4 5-speed is nearly a perfect setup/compromise for both GT and sport driving on the street.

For pure sport driving I have a full-cage street legal GT racecar with Bilsteins and drives/handles like a dream - on smooth roads or on a track. Therefore, this setup is not recommended for GT driving as it gets old quick on rough roads.

Here is an example of rough roads. There is a stretch of road on Interstate 94 when heading north to Road America or Green Bay, which is 5 miles south of Hwy 57 to RA.

It turns to concrete, and the GT racecar goes bang-rattle! bang-rattle! 2 times per second for 5 miles and seems like an eternity. The whole time I'm hoping nothing breaks or comes loose. In the S4, it's maybe half the intensity of the GT, and I'm not worried, just annoyed. In the Rav4, no problem, just a bump bump bump noise.

I'm giving you these examples to show how important your choice is for how you typically like to drive your car.

SeanR

Then he's got them on full hard. Medium setting is just slightly stiffer than stock boges but less so than Bilstiens. Soft setting is more in line with stock Boge's.

If you install them properly you can adjust them in the car with minimal disassembly and the right tool. Most that I see installed by amateurs do not widen the dust covers holes and this makes it impossible to do it with them in the car. Hell, I've seen many that just don't put the bump stops or dust covers back on because it's apparently too hard to do it right.

SwayBar

Sean, thanks for the heads-up, I'll relay the info to him.