Of course there is a difference in the shocks. Just look at shocks for a wagon, they are $200+ a piece. On cars with self leveling systems, there is a hyd. line that goes to the top of each rear shock. What do you think the hydraulic fluid is for? The accumulators (nitrogen cells) are what pressurize the hydraulic fluid that goes to each shock to raise and lower it.
1994 MB E320 Coupe (199,500 mi)
1992 MB 190E 2.6 (173,000 mi)
1983 Porsche 911SC (148,000 mi)
2004 Volvo V70 2.5T (198,000 mi)
President of CT/Westchester Section