This happen a month after I put in H&R sport with stock shock/strut.
It sound like metal hitting metal noise coming some where form the RSM area.
It only makes noise when driving on rough road not bump or speed bump.
The dealer said that the noise was cause by the sway bar hitting the exhaust due to lower spring ( I also have SS exhaust ).
But to me the noise sound higher up in RSM area rather than from
the bottom of the car.
Any help will be appreciated.

Did it start making the noise immediately after you had the new shocks put in, or did it take some time for the noise to start? If immediately, check the washers/spacers securing the shock to the RSM, to make sure they're in the right way. Also, check to see if the paper gasket between the RSM and the body of the car is in place. Torque all the bolts holding the shock to the car. Check the RSM to make sure that the center hasn't separated from the rubber.

Also, put some crayon/chalk/paint (tempera water paint) on the sway bar to see if it gets transferred to the exhaust when you go over these bumps. If it doesn't, then your dealer is wrong.

Jim

It happen a month after I replace my spring.
I lift the car up I can see the mark on the sway, but to me
when I fold the rear seat down the noise is exactly from the RSM
area. I thought that if RSM is bad it will clunk when go over speed bump slowly, but it doesn't clunk tho.