Not sure my self about the PS3 slim, my mate told me it works so I just took is word for it.
For bi-amping. You should not lose any bass at all, but it just may be clearer in the treble that makes it seem that way.
But to be sure, have you a SPL meter on hand, as you can take a measurement with the test tone bi-amped and in normal mode, if you have no SPL meter then check your manual to see if there is pertickler way you should have the AMPS feeding your speakers, as for my onkyo, it says to have the normal left-right channel feeding the tweeters and the others to the bass units.