when connecting power AMPS

I have an integrated Amp (Exposure 2010S) but its also capable of a pre-out. My question is when I connect a power AMP -- will the sound 'signature' / 'charateristics' be coming from the AMP or from my Int. AMP (as pre amp).. I really love my Exposure but wanted to add more power.. I just don't know how it will sound when added other brand of AMP.

thanks

jason