I'm getting H&R springs and I will only use the fronts for now. Here's my thinking. (Wise input welcomed.)

H&R springs are reputed to be softer than RennTech or Eibach. I'm still using the car 360 days/year on the street, so I liked the idea of softer spring rates. Firmer than OEM, but still soft.

The H&Rs only drop the front 1" which is less than the other springs (Eibach/Renntech) lower the car. I wanted to get down to where the current C55 and other C-class cars are in height. This should do it.

I'm using stock shocks so I will not have a gross spring/shock mis-match.

I'll drop the front center of gravity, but keep a safe ride height.

Dropping the front might induce a bit of negative camber (good); but more importantly, it won't hurt things.

Keeping the rears as-is is my plan to avoid creating positive camber because I'm not sold on the KMac product just yet, and I'm trying to limit my investment. I can certainly go that direction later.* So, I'll have some rake (but I doubt it will be noticeable).

The only possible problem I will create is that, by firming up the front (which H&R will do a bit I suppose) while keeping the back softer, I create a formula for more understeer. But firmer front and lower cG should also help turn-in. We'll see how it turns out.

It may be beneficial, to keep the rear soft since one of the downsides to firming up the rear (springs, shocks OR stabilizer bar) is that you transfer weight to the outside wheel faster/harder, and reduce inside rear wheel traction; and that can limit your exit speeds -- i.e. make it harder to accelerate out of a turn because you are spinning your inside, rear wheel. This is particularly the case with our non-LSD cars.

I won't install until some time in March/April, so I'll be staring at springs for a month or two.

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* Alternative thought - input requested. Is it possible to use a lowering spring in the back, but to negate the lowering by using a spacer? I know that Benz has spacers in the back of some models, and if I can use a firmer spring and negate the lowering, then I will eliminate the positive camber issue without KMacs. I sound obsessed with this positive camber thing, but this Benz tech/racer told me that a static positive camber gets even worse when the car is under heavy lateral Gs. I also have no problems with my rear ride height.

Does anyone know whether bigger spring spacers are available for a C32?

 

I believe that doing so will also shift the COG forward as well, resulting in a bit
more forward bias. How much, I don't know. Whether you'll notice the diff,
I don't know. But this is one of those 'all things being equal' theories....since
pitching it down while keeping the rear up would prob result in the above. In
addition, since there will be weight shift, you might also end up with more static
spring sag than had you installed the H&R rears, you think?

All this is theory stuff, sitting behind my keyboard.... will leave the confirmation
to those who finished school.

 

i wanted to do the same thing but this was strongly discouraged by speedtechnik. in fact, Mitch flat out refused to do it. i respected his advice - he and his shop run a race winning world challenge bmw 325.

the h & r rear bar would probably do more for handling than the front springs alone (assuming they work and not upset balance of car under cornering loading).

if you do go this route then get the 2 shortest spring pads for rear, take out your stock ones and then gauge which would be best for replacement (lowering). you can then return the unused set of pads. they are cheap i think $7 a set. simple way dial out some of the nose down attitude.

also don't think you can get -ve from lowering the front. the susp geometry will not permit.

also the reasoning re soft rear spring is incorrect- it's the opposite. kind of like the effect of a stiffer rear bar.