the best way to get that 80's sound is to make it, i suggest learning how to sound design the sounds you want, by getting a synth, find the desired sound you want, then clone the same synth then take the synth you just cloned and make it to a default preset, then tweak the preset to match the synth above while playing with some notes, to see how the sound is developed, although the sytrus is capable of making some nice sounds, i would not suggest using FL studio for main synths, mainly because FL studio synths are really nasal and can hurt your ears at times.