I've had good success with the spring shocks. The 4 pair I remember on big sedans raised the rear at the wheel about one inch. On the Darts and Satellites, it was about 2 inches. More if the springs were weak, less if they were not. I didn't notice any draw backs.
I put four on my long wheelbase 3/4-ton 97 Dodge conversion van last year. They raised the front at least one inch. I don't think the original front coil springs were tired or sagging, maybe an inch at the very most, if any.
They raised the rear FOUR inches. The rear leaf springs were sagging "at least" two inches. That may have been because of weight added when the conversion was done, and maybe not worn-out springs.
It's a big improvement on this van. The van doesn't rock back and forth more than one time at an aggressive stop now. As opposed to three oscillations with the other "new" Monro economy front shocks and "new" Monro rear air shocks I installed a month prior. The rear air shocks did fix the rear lift problem, but the hydraulic part was sorely lacking. Both front and back.
That rocking was annoying. Now the nose drops/dives and rises/returns one time at a hard stop. And, the 5,500-pound van rides better now than any of the other dozen vehicles I have. Go figure. But, the pillow soft 78 Grand Marquis is gone, so it don't count.
So yes, I do think they raise a vehicle. And can be useful on the right vehicle.
