I really like this site, and often drop in to have a read (and a chuckle sometimes!) but I find threads like this pretty frustrating. A little bit of misinformation, followed by a little bit more to back up the original statements, then tweaked & tuned to further justify, just end up being a pointless effort for the poor bloke who was trying to get some simple advice on lowering his little datto.

A few facts to consider:

1.There are many, many club & state level racecars accross this land that use various arrangments of the standard leaves to achieve the desire combination of spring rate & ride height
2. I have never ever seen one of these arrangements fail.
3. The amount of load put through these springs in competion is harsh to state the least. Huge increase in power over stock, much sticker tires, locked diffs, big brakes etc.
4. You can improve the stock assembly when doing this (if you are so inclined) by replacing the centre bolt with a high tensile item, clamping a turned spacer that very accurately locates the diff housing to the spring.
5. This repeated reference to stiffening the spring rate is also misleading. You may find that if the suspension is being reviewed as a whole, soffter rear springs, shorter shocks & a sway bar MIGHT be a better overall solution. Note MIGHT be, I am not going to presume what Demo's driving style is like so I am not going to tell him he needs stiffer springs just because he is lowering his car.
6. There is another possible benefit to lowering the car by rearranging the leaves, this would be to "over-lower" the car, thereby necessitating the extension of the rear shackles to gain back some ride height which will also help get rid of some of the in- built roll understeer in these cars.
7. Lowering blocks of any height are probably last resort. Due to the increased moment they acentuate any axle wind up. Probably OK for mild street car but not ideal.
8. Comments like "everything else is unsafe & may be downright dangerous" are just inflamatory and scaremongering and shoudn't be encouraged on this site.

In my own racecar, I started off with professionally reset spings, reversed eyes etc and actually progressed (if you can call it that) to home made spring packs that let me fiddle and tune to my hearts content.

Hopefully there is not a response that starts with "So let me see if I understand..." Pfft