I have an AP1 S2000 rolling on OEM AP2 wheels.

The specs are as follows:

17x7 +55 F & 17X8.5 +65 R

Because of the extremely high stock offset, the wheels are very sunk in, and I'm looking to flush them out towards the fender with some hubcentric spacers. This is purely for aesthetic purposes, though I've heard that increasing track also increases stability (?). Perhaps something like Ichiban, H&R, Kics etc.

I was going to go for 20mm on the rears, and 15mm on the fronts. This seems like a good sizing choice to avoid guard flaring. I think it only needs a tab relocate and some rolling.
For the time being, I will drop the car on an Eibach lowering kit, then move on towards KWV3s middle of next year, either that or straight onto V3s. Not too sure at this point in time. If it's any help the car will be lowered about 1-1.25 inches.

My concern is:

What effect will this have on the component tolerances? I've heard it can be detrimental, as you are essentially increasing the length of the axle, making things easier to break; the longer length provides more leverage which decreases the force required for breakage.

I've also heard that this increases something called mechanical state steady understeer, which diminishes the overall level of grip.

The car will be seeing street driving, country driving, track and DECA days. I want the look obviously, but form follows function. I don't want to lose any performance because of it. In addition to this, the last thing I want is a wheel coming off mid-corner or long term degradation of components resulting in very expensive fixes down the track. Some of you might say well, why not just get aftermarket wheels. I want to keep my car looking as factory as possible, so at this current point in time that is not an option.

Thanks everyone for your help.