replacing stock speakers

i have a 2015 tacoma double cab and would like to keep the stock radio. if i replace the stock speakers with after market would the sound be better?

 

Generally, no. More power is typically your first step in a stereo upgrade because that's what has the largest impact.

 

My experience was that better speakers have much higher sensitivity and are louder (stock speakers put out about 84 db/watt, new JL's are 91 db/watt - estimate based on comparing the two doors with a low grade sound meter). I put 3.5" kickers in the dash, and JL's in the doors.
The dash speakers are much more in line with your ears, than the door speakers. Therefore they are much more effective at transferring the high frequencies to your ears, than the door speakers can. I had to reduce the output of the dash speakers by adding 4.7 ohm/ 5watt resistors in series as they were too loud and caused a tinny sound. I also used a 47 uf/25 V non-polar capacitor in series to limit the bass. Without the cap, the cones were jumping 1/4" and distorting a lot. I tested different values before found this combination to have an acceptable balance between the dash and the door speakers.
The sound is both louder and cleaner. Did have to trim some plastic to get the dash speakers to fit, but the outcome with the stock radio is just fine; and I am quite particular about sound.
Now in the process of adding some acoustic dressing to the doors as the door panels vibrate and the door cavities resonate.

 

Pair new speakers with something like alpine 445u or the kicker key amp