advise wanted on 4" component system

[hough]

hey i after some help, im looking at some new speakers for my bmw e90 i think my mids are 4" and there are 6 or 8 inch subs under mr front seat so should i go for a 2 or 3 way setup and to power them i have a 4 x 60 watts rms amp and if going 2 way and you also recommend a 6 or 8 inch sub that can run on 60 watts