I just helped my 16 year old replace the front speakers in his 2000 f150. He got 6x8 Rockford Fosgates. We also replaced the head unit a few months ago with a pioneer. Nothing fancy but better than stock. The factory speakers were getting distorted so I figured that the replacements would help a lot.

Well kinda disappointed. No real help with volume as they still get distorted. Do I need an amp? I don't know much about audio but can read instructions and usually even follow them.

 

An amplifier always helps. If you are pushing the ill equipped power form a POS factory
stereo or a budget one then yes it will sound like crap. If that stereo pushes distortion
at say volume 20 then anything beyond that will sound bad and potentially blow a higher wattage
speaker due to that distortion. A lot of people think that 20 watts is enough power
to push speakers, it is if you are 80 years old and listen to talk radio all the time.
For full body sound with the windows down I would push no less than 50 watts
RMS. When a stereo proclaims a wattage it does not tell you that with .0001 THD.
It just tells you max output and don't worry about distortion. Any Stereo whether stock
or after market will sound immensely better with a amplifier that puts out 50 watts per
channel RMS rating minimum.Like I said, a stereo's output is not enough power to push
much of anything at any significant volume without distortion and that is why amplifiers
are so important. Properly adjusted can make a lower budget stereo sound significantly
better than factory without shattering glass or your budget..lol