I'm not a stereo expert by any means, but "Ideally" I would say yes, it's probably better to maintain the setup of components vs coaxials. Having said that though, I've got the Kappa 62.9i's installed in all four doors and it sounds freaking awesome. The sound is so much clearer than the factory speakers and having the stock tweeters still hooked up in the front doesn't make much difference in sound with the kappa's hooked up. The tweeters on the kappa's scream and are much louder than the factory tweeters. If you're on the fence about buying the kappa's I would suggest to hook up the pair you bought in the rear and just listen to them compared to the fronts. They'll blow the sound quality of the front door speakers away and you'll be convinced that you have to have the fronts done also. I was really amazed at how good these sound. After installing the first speaker in the rear door and listening to it I could already tell the sound was wayyyyyyyyy better over the stock speakers.