From website 1, "By the way, since installing the wheels and spacers have you had the alignment checked? Spacers CAN and sometimes do cause an alignment change. This will cause poor tire wear and steering return performance. To check the steering return drive around the block a couple of times Right turns then left turns. When you turn and let go of the wheel momentarily the steering should self return to center straight. If not your alignment may be off
ASE MASTER CERTIFIED AUTO SERVICE TECHNICIAN"
From website 2, "Wheel adapters always change wheel geometry. Due to the way in which they are installed, they cause the vehicles footprint, or stance, to become wider. This changes the alignment geometry and front-wheel alignment must be performed to ensure proper steering and cornering. Front-wheel-drive cars require the rear alignment to be corrected as well." Above is about wheel adapters, not spacers, but the same geometry applies.
All-in-all, for no discernible benefit, why should we bother?
I have some pretty aggressive suspension on my 240sx. All solid joints, setup for autox. I have 10's in the rear and 9.5's in the front. The offset is 10 for the rears and 25 for the fronts.
So when using a hunter system having the rears stick out further wont throw the rear toe WAY off? My alignment guy has to compensate for the wheelbase. Also using aftermarket wheels its advised you get hub centric rings for your rims, if your using spacers that you get from pep boys, they arent hub centric. The stress on your studs and hubs would be insane.
The only reason use spacers it to fine tune wheel fitment, or space them away from calipers, but I dont see many people running anything more than 5mm.
I also have +40mm offset wheels and my car is just as fast through the corners at legal speed. Get a sway bar, better shocks if you want better handling, because even with the biggest spacers your car will still roll the same with the OE sway bar/suspension(shocks/springs) - your tires will just hit your fenders faster.
You're making the questionable claims. Support them with factual testing, or give up. You've already been shot down by darn near everybody who's posted, on darn near every claim you've made. We're citing facts and experience. You're waving blue smoke and mirrors.
By any logic I or anyone other than spotaneagle can figure, spacers can not produce the kind of results that spotaneagle claims. I cannot find a logical reason why they would produce any handling advantage except possibly on a pickup truck or RWD muscle car, nor any fuel economy increase.
On the other hand, spotaneagle has gotten results, which work for him; it doesn't really matter why, as long as he's saving fuel. I am not confident that anyone else would achieve the same results.
This thread will not produce any further data or useful arguments that will help anyone. There is no need to continue.