How old are your rear links? They were updated in later cars ('93 methinks) and might account for the sway. Or, could it be the front? Check your front sway bar attachment "links" - they are cheap metal and snap occasionally (but it assuredly feels like the front washing out, so likely ain't your prob but I thought it worth mentioning)

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"If God had meant for us to walk, why did he give us feet that fit car pedals?" Sir Sterling Moss

Michael
2014 E63S Estate
2006 SLK55
1995 E500
1986 Porsche 944 turbo