Power Question

If I am building A P3A for the low pass, can I build a well matched biamped system with a P10 as the high pass amp? More specificly, what Xover frequency would I need?(assume a Linkwitz-Riley) I have some POS speakers for the mids and tweeters, but the subs are MTX Thunder3000's. I know NOTHING about the POS speakers, but the MTX's are marked:

1OMC1280 4 OHM
557 99-05-24
Is this (model#, impedence)
(datecode) ???

Jake