I currently have polk audio db 5 1/4 speakers for the front and rear. Im planning to upgrade to polk audio mm6501 6 3/4 front and rear. Will i have fitment issues? Anyone running that setup? If so, how do they sound? Where a good place to buy speaker bafflles or speaker adapters? Heres a pic of the speaker:

 

i got 6.5 in mine and i dont have any issues. cant be certain what an extra .25 inch will do though. my best guess, nothing.

 

Make the speaker baffles yourself, it's very easy. Take the stock speakers, trace onto a piece of cardboard, marking the mounting locations. Then trace out the mounting hole you need in the middle. Cut out the cardboard template and trace it onto a piece of 3/4" MDF to cut. Make sure you weather treat it though, so it doesn't get moldy on you.

Pretty sure 6 3/4" will fit, but I haven't tried it myself to be sure.

 

That is the answer to your question!

 

They will fit,at worst you will need to trim some of the panel back to get proper clearance,but they will fit.......my question is why add rear speakers......I did abd then took them out and bumped up the amps to the fornts and it sounds louder and cleaner,no cancelation and now saving money......that is a plus.

Really when you amp a comp.......you wil not need rear fill at all......it is plenty loud and I meen plenty loud.....fills the whole car and then some,...adding a rear stage does nothing for our car or many others.........really....take the money and enjoy it on other mods....trust me......I wish I had.