I am looking to get opinions about the best options to replace the factory speakers in the front and rear doors. Ideally, I would like to leave the factory head unit and not add an amp. I was hoping to find speakers that could add a little extra low end to round out the sound without adding a sub, but I know that might be wishful thinking with 6.5/6.75 inch speakers. I don't need heavy bass, just looking to improve the overall quality of the sound and not break the bank.
I have looked at Polk db651s (do I need to get the shallower speakers or would the db651 work?) and Infinity 6032cf/6032si as these are the brands I am most familiar with. I have also heard good things about MB Quart and Rockford Fosgate being more efficient
speakers and possibly a better fit when working with the factory head unit?
Would it also be worth considering swapping out the factory tweeters? I would like to install everything myself and it will be my first time so I am looking to keep it simple and my budget would ideally be under $200. Any experts in the field- I would greatly appreciate opinions!
I have looked at Polk db651s (do I need to get the shallower speakers or would the db651 work?) and Infinity 6032cf/6032si as these are the brands I am most familiar with. I have also heard good things about MB Quart and Rockford Fosgate being more efficient

Would it also be worth considering swapping out the factory tweeters? I would like to install everything myself and it will be my first time so I am looking to keep it simple and my budget would ideally be under $200. Any experts in the field- I would greatly appreciate opinions!