reccomendation for a crossover

what would you reccomend for a crossover(s)...i have one four channel amp and two mono amps...the mono amps will be at different frequencies..one for 10s and one for a 15.  the amps have crossovers, but i imagine i can have better control with an external crossover...i am also considering an epicenter...probably for 10s?  not sure yet...i know i want one for the 160spl in dash meter, but im not sure which sub(s) to hook to...

that was a mouthfull!!!!  what are your suggestions?

ahh...i like...just a simple x!

OK, what you're looking for is something like the Audio Control DXS crossover.  This is a three-way digital Xover with 24db/octave slopes and some other interesting features.  You do not want the Epicenter for this application.

With a DXS (or a similar three-way crossover system like a JBL GT47X) you send it a stereo signal from a main pre-out off your head unit (the rear channels, for example.)  Use the low-pass output from the DXS set at, say, 80Hz to drive the amp you use for the 15.  Use the bandpass output (NOT the same as a bandpass enclosure!) from the DXS set between 80Hz and oh, say 250Hz to drive the amp for your 10.  Use the high-pass output from the DXS set to 250Hz to drive the amp for your rear channel main speakers.

Will this make much difference?  You will probably notice a better bass response in the bandpass frequencies since a 10" woofer will be much better between 80 and 250 Hz than most smaller main speakers.