ahh.. the mechanic trying to suggest you some other brands of damper for the suspension... I'd tend to reserve Eibach for the serious guys though... the Kayaba (KYB) usually holds fine with stock cars.
Then again I don't own the exact same car, so I can't say much other than your damper may be different than the USDM model... or... the nissan assembly kinda screwed up somehow..
these might be wrong:
-damper rod not fully tightened
-no plastic sleeve over the spring coils
in any case, say hi to the nasi lemak booth down the street.
