This is based on experience.
Nautilus 805 and Rotel RA1070 integrated
Bi wire : very minimal to no results at all for the investment. This was the first step that we tried before we bi-amped.
Nautilus 805 and Rotel RA1070 plus RB1080
Bi Amp : big investment but the results are outstanding. More control by the amp over the drivers since every amp channel will drive only 1 speaker driver. Bass is more authoritative and the over all sound has more body.
YMMV though.