regarding to rear fill or not to rear fill the best thing you can do is just read everything written in these forums then find an audiophile who knows what hes doing and is running only front speakers and sit and listen to his system-----then you need to tell him you need to borrow his car for a week or two and just drive and listen.. drive fast drive slow drive while smokin crack whatever you normally do when driving do it and listen. then tell him your gonna alter his finely tuned $10,000.00 system slightly and throw some 6 X 9s in the stock back location and do the driving and listening all over again. if he hasnt beat your azz by now you should have a pretty good idea whether you want rear fill or not. personally i had a freind set up my car with what he considered to be of almost optimum sq audio in my situation (meaning my car and finances --drug habit etc). in conclusion and i tried to tell myself i was now an audiophile and that listening to only front speakers is what all us true audiophiles do-------when i got real ---to me it ****** as compared to when i threw my 6 x 9s back in and cranked it up and realized ---im no audiophile --im a 42 year old guy playin the hell out some trickdaddy thinkin im cool and in my lil car audio worrld ---i think its cool and thats all that matters. yeah my freind came back at me with all the hypothesis and algorithms or whatever the hell he said ---attenuation --cancellation---whatever---all i know is dammit when i crank dat new fat joe joint i have a smile on my face and **** cancellation--go ahead and cancellate i dont care. with the amount of money your spending you should no doubt have a great system. just figure out what you want out your system --read as much as you can---preferrably listen to other systems then go for it and hope its what you like. chances are it wont be and youll spend another 2 - 3 grand trying to get what you want. but hey thats the joy of car audio its what us guys do---we spend insane amounts of money changing systems that most people thought were the bomb--but thats life. gurls buy fifty pair of red shoes and will almost die telling you the importance of having all 50 and that life isnt worth living without them---just like we tell them -honey i wont be happy unless i get this eclipse amp and straighten out my system as they go in the closet and pull out 8 other amps and we have a valid reason for every one of them being wack and **** she trippin. but my main moral ----yeah i guess i coulda just said this in sentence two and been done with it but oh well----dont let anyone tell you what you think sounds good. oh they will try but in the end its your cash and its your happiness. id rather have my **** sound good to me and have my buddies all hate it then have my buddies tellin everyone my system is bomb and i think it sounds like garth brooks (pick a song any song they all **** to me) (thats right for all you mentally challenged that was a country music diss). well have fun and i know ive been of no help whatsoever and i apologize for that ---why dont you give me the 2 -3 grand and ill upgrade my chit and you can listen to it when i drive by your house with the windows down. take care and good luck