I heard you can do both the front and the back and achieve 4 inches, like previously posted there are a lot of other (read better) options available. I think that amount of lift may cause other issues with caster balls, uni joints and the general handling of the vehicle.

Like all other urban legends, try and find someone who knows what they are doing and has actually done the mod, I doubt you will, but if you can find them, talk to them about any other issues that have needed to be addressed with the cheap fix.

With the relative cheap cost of D1 springs and shocks you may only pay a bit more for new uprated springs than you would for a pair of used 80 series springs from the wreckers anyway.