Amp for Polk Audio Lsi15

Hi all,
first time poster. I recently bought a pair of Polk Lsi15 speakers. While they sound great, I feel they have more to offer. I know these like a lot of power, and my current amp (Adcom GFA-5300) only puts out 125 WPC @4ohm. DO you think a more powerful amp will really make these sing, or am I better off upgrading their crossovers. I'm hoping to improve their detail and imaging. I have a lead locally for a NAD 2700 THX. would that be a good match for these speakers? Im new to all this, so any input is greatly appreciated!

I used to own the LsI15 speakers and used an Audible Illusions S-120 amplifier. The amp was rated at 120 watts into 8 ohms and 240 into 4 ohms. They sounded great with this amplifier.