It should be in suspension....but if he/she has a v6, I can understand why it was posted here...the suspension for the 6s is different then the 6i in terms of engine weight load.
I think what he means is this...when we see a lowered car go over a slight bump...we see the car's suspension bounce more dramatically compared to say a car that is stock.
The bounce he referring to is in essence similiar to a pogo stick...where on a pogo stick the spring compresses, but then bounces back in an equal an opposite force.
So to answer his question...the answer would be yes...we can expect a result like this on many of the aftermarke suspension kits.