[Gamb1t]

IIRC the HK amp that comes with the Top HiFi option is not a direct plug and play over the HiFi version. HK amp uses optical cables I think. Also HK system has more speakers (rear tweeters + center channel). Can't remember. BTW, the Base model is powered via headunit.

There are cheaper and better upgrades than going from HiFi to HK for sound upgrades. HiFi amp wiring is normal audio cables therefore aftermarket upgrades are easier. Search around the audio sections.