C4 lowering, Whats needed?

I have a set of H&S springs ready to be fitted for my '00 C4, and yes, the springs i have are the C4 specific ones, before anyone asks. My car has had all four dampers replaced 18 months ago, along with a few other suspension items, front coffin arms and tie rod ends, and a few other bits I cannot remember, so, it should be in good shape to lower. My specific question is regarding geometry once lowered, will I need to get any other parts to get the geometry back to within specs once the springs have been fitted? Also, will the standard ARB drop links work as intended once lowered? I love my 996, but cannot live with the SUV-esque ride height of the standards setup.

It depends on how far you are looking to drop the ride height? -10mm and there shouldn't be a problem -30mm and you may need to start looking at rear parts to aid getting a good geo setting

If lowering its recommended to slacken off the bolts hold the coffin arms and retighten whilst its on its wheels. Lowering it will put a permanent 'twist' in the metalastic bushes.

Aha! there is lowering and stiffening. My C4s has turbo coil over shocks and springs and to my wife it is too low and too firm!!! She has asked me to make the car higher. So i contacted center gravity yesterday and raising the ride height alters the camber at the front and rear which means a 5 hr set up and about £450+ but you get a properly set up car. If you do what you want then it will be the same process for you but in reverse. I am thinking of buying her a cushion

Depending on how low you go you might want to consider different dampers. The low springs will not have the dampers sitting in their optimal position. Hence why bilstein have 2 different dampers with exactly the same internals except the B6 are for stock springs and the B8 are for lowering springs. Probably won't make massive difference to handling but they might wear out quicker

- 30mm Lower and you may need adjustable toe arms on the rear to get the camber/toe adjustment correct, I did when I fitted -30mm Eibach springs.

H&R quote the sprigs as being -25mm but I guess that will be +-5mm depending on the healthy of the other components. I guess I'd be best off speaking to the likes of CG or 9e as to what, if anything, in their experience would need to be changed to retain the geometry settings.

problem is that with both the H&R and Eibach springs (I have had both) they say they are -30mm in the rear but they are both the same at about -50mm, so out of range for adjusters without having lots of neg camber. Solution is to use different springs (I think someone recently found spax? didn't drop the rear too far) or shim up the rear pearches when fitting the rear springs some guys had 10/12mm shims made up so the rears did not drop so low and normal adjustment for the geo in spec.

I fitted 10mm spacers to my rear springs when I couldn't get the car aligned but still needed adjustable toe arms to get to X74 spec. If I did it again I'd probably fit 15-20mm spacers, I don't have any rubbing issues with 15mm wheel spacers but that may be because I've rolled my arches.

I have H&R -30mm springs on mine (with Koni shocks)... My Indy had no issues getting to X74 alignment with stock suspension parts. Springs lowered the car equally front and rear. Minimum drop to make a 996 'look right' IMO.

koni Are your shocks Koni FSD? I have bought a set of the special actives which replace fsd and a set of eibach springs and I am hoping my ride height comes out just like yours but on a 993!

No, mine are Koni Sports.

Thanks for posting that picture, it looks spot on in my eyes, certainly not - 50mm on the rear, really looking forward to getting the springs fitted. Having had a chat today with 9 Excellence, the people I'll probably use for the geometry setup, they confirmed, if all the components are in good shape, achieving their fast road setup, which inherently has a little more camber than srandard, is not an issue. I wonder if the setup they are referring to is the same as, or similar to the setting used on X74 equiped cars?

Personally, I think there's a lot of bollocks talked about suspension settings... there's only so much you can do with standard parts... a bit more camber, and bit less toe, but nothing earth shattering. X74 for example, is only a bit more rear camber... rest is same as stock. If the components are good any decent Indy with the right equipment can get the alignment right. Biggest change you can make is to run less rear toe... I'm running 15' (vs 20' stock)... but also have a H&R adjustable bar on full stiff and a M030 front bar. Different story if you're going full custom with coilovers and want custom spring rates.

Yes, I would agree with stotty that a lot of bollocks is talked about suspension settings, but also he is literally the only forum member I think who reports their indie had no problems getting x74 settings with h&r springs. Don't get me wrong, it's entirely possible to set up a 996 with Eibach or h&r -30 springs but the majority end up with having more neg camber on the rear than x74 spec unless you get lucky. it goes round corners really well and seems OK to me on motorways but I guess it's going to munch the insides of the rear tyres quicker than usual. I'm not bothered enough to care about it not being in spec given it seems to work just fine but others OCD may not allow