High-pass filter. Yes or No?

In my opinion you should put a high pass filter on the midrange speakers if you have a subwoofer handling the lows.  The component crossover handles the cross between the midrange and the tweeter, but does not put a high pass filter on the midrange.  Without a high-pass filter there's a good chance they'll bottom out when the music is loud and low, causing audible distortion and potentially harming your speakers.  Most new head units come with some sort of built-in electronic crossover.  Does your deck have this feature?  If so, I'd recommend using it.  Are you going to put these new speakers on an amplifier?  If so, most new amplifiers also have some sort of high pass cross feature.

OR you can use a passive crossover, building your own or buying them for a cheap price. 

SoundDomain has some here:  http://www.cardomain.com/shoplist~b~Lightning+Audio~t~Passive+Crossover+Components

Crutchfield has some here:  http://www.crutchfield.com/S-BX83qzSDBux/cgi-bin/ProdView.asp?s=0&c=11&g=761&I=127BB150A2&o=p&a=0&cc=01&avf=N&search=bass+blocker