diamond audio m561's

I could use some information from the gifted please. I recently purchased 4 Diamond Audio m561 woofers with 2 of the m561 crossovers and 1 of the component tweeters from a pawn shop. I paid 75.00 for the package. I also held my breath until I had paid and exited fearing this too good to be true. It wasn't and I step up to Diamond Audio front stage. The tweeter is bad but I have several other sets to replace it. Woofers (midbass?) are good as well as the crossovers. Notice I didn't mention manuals or documentation. The crossovers are fairly straghtforward but they have provisions for 10db attenuated down rear fill full range speakers. All drivers are 4 Ohm. I know that my amp sees 4ohms from the separates but does it still see 4 ohms if I use the rear fill option? (Assuming 4 ohm rear speakers of course)Currently the front stage is run by an older Coustic 260 amp but this is to be replaced by an older PPI 4200AM. I would like to show the amp a 2 ohm load and am intending to try adding the other set of Diamond Audios to the front and allowing them to roll off naturally in addition to the component set. I would prefer not to use rear fill at all and I'm concerned about the SQ with the second woofer, but I would really like to hear the PPI flex its muscles. I'm not a competitor but I try to copy as much of the trends as possible. My sound philosophy is; I want to drink excessively, turn the system up until my ears bleed and I don't want to have to apologize for a single pop, crackle or growl to anyone else listening.(No I don't drink and drive and yes I am aware of the danger of excessive noise levels.) I just want the system to be capable of it. Help with the impedance questions would be appreciated and recommendations about the rear fill or second woofer would be helpful. Go easy on me guys!