Do any of you feel that there's more lateral movement in the rear suspension compared to other makes? I purchased my Z in December so most of my driving time has been on winter tires.

Last week I switched back to the RE040s. Since then, I find with harsh bumps, the rear seems to jiggle (ie: small lateral movements). It's really odd and the suspension feels particularily distrupted.

Could it be because of the make of tire, or the large change in unsprung weight - 16" steelies with 215 to 2.5lbs 1" spacers plus Touring rims plus 245/45 tires?

 

I would suspect rear alingment may be off.

 

i agree...when the rear toe is off, the car tends to steer itself from the rear. this is a pretty unsettling feeling.