NHT SPEAKERS

NHT C3 bookshelf speakers? and NHT C LCR Center speaker thoughts??a person i know is selling me these speakers for $700 perfect condition i currently have a DENON AVR S970H would these pair well with my reciever? mostly listen to home theathre Amazon fire stick streaming and hip hop music, Any help would be nice fellas Thanks! (ps i would need a subwooofer right? any recomendations??