I'm thinking about lowering my S430 just a little and have few questions for those that performed the Washer method.

1. Height Adjustment - how much lower does your car go with each washer (about). I would like to lower it about .75 of an inch, maybe an inch.
2. Tire wear - do you get uneven tire wear after lowering
3. Reliability concerns?

I also haven't been able to find a good guide/how to. I know it's pretty simple.

I might do the guide myself...if I decide to proceed.

 

I tried washers &, I had to get lower. I went all out with 3 washers which were somewhere between a dime & a nickel thick. This allowed me to JUST be able to grab enough thread to feel secure. My car came down about 1.25". I didn't try less than 3 but I'm assuming you divide 1.25 by 3 & find out how much an individual washer will drop your car. Overall, it is a nice difference but just not enough to really look lowered. I know at least 3 guys that stripped the nut on the bracket that attaches to the upper control arm so, keep in mind that the bracket isn't going to like being over-tightened.
I bought $75 links from ebay & I have gone much deeper than washers with zero loss of performance nor reliability. Installing links is as easy, maybe easier, than washers except for getting them adjusted to the height you want. I would not pay a ton for links. Obviously, they're more than washers but it's a very simple design & fancy links will do absolutely nothing more or less than the $75 set. For all I know, they may cost even less now. I ordered mine from a place in Southern CA.
However you lower you car, you're going to need to loosen your lower control arm at the frame/axle carrier & then re-torque it down while it's under load. Essentially, you'll jack up your car, loosen the lower control arm bolt, put a jack stand under your steering knuckle, then drop the jack so the jack stand is bearing all of the car's weight, Then, re-tighten the lower control arm. If you do not do this, you'll burn through tires & have a greater chance of ball joint failure. One ball joint takes out another & then you're replacing all but your struts. Torque specs are: Spring control arm to axle carrier 80Nm then 120 degrees.
Also, remember that you're only tricking your car to lower the front end to so, you're probably going to want to adjust the rear end. There are no washers or links needed back there. It's already adjustable & there are a handful of write-ups to guide you through that. It's a simple job.
I'm assuming your car is not Airmatic. If it is, I believe I'm still correct regarding the washers but, when you want to go lower with links, the rear will need an adjustable link as well.

 

As far as how to install washers, it's very easy. Jack up your car & remove your wheel. Run your fingers up the top of the rear half of your upper control arm. You'll feel a small nut which I believe is 8mm. Could be 10 but I'm pretty sure it's an 8. Remove that nut. Pull out the bracket attached to the nut you just released. Put your washer(s) on the bolt. Put the bolt back through the hole & tighten down the nut...but not too tight as I know a few people that have stripped the bolt.
As I mentioned in my other comment where I mostly suggested links, you should loosen the lower control arm at the frame & re-tighten it while the suspension is under load.
Get the wheel back on the car.
Repeat on the other side.

 

Hi
Which lower control arm do your re-torque? There are two of them. The strut arm (connects directly to the air strut) and the thrust arm (I think it's called) which connects the knuckle to the front of the vehicle. Do you also do the upper control arms as well?

 

Anywhere there's a rubber bushing, it should be torqued at ride height to avoid preload and premature bushing failure. There are 4, 2 per side, attached to the front cradle.

 

Not meaning to question ItalianJoe's input but I'd only seen that the lower, rear arm, or strut control arm, was what needed to be re-torqued for lowering.
I certainly torqued down my upper arms, under weight, when I replaced them but didn't think about it for lowering as I'd only read of the lowers being important.
Doing the uppers makes sense due to the bushings but I've never done them for lowering.