undepowered speakers

I have 1997 Mmercury Sable.
Recently I canged factory speakers to one pair of Pioneer and one pair of Panasonic. Each is abbout 150W output. When I crank up the volume on my factory stereo distortion occurs. I'm aware that its due undepowered speakers. I know I can replace head unit but thats a pain because I'll have to get and adapter because my stereo includes rotary climate controls.
The second option is getting an amp. But thats requires more time on installation and probably money and I don't have much experience so i'll have to pay for installation as well.
I don't need a great sound but I'm not satisfied with the sound produced by good speakers and factory stereo.
So, i'm in the need of advice what do do, what choices I have.
Thanks

you basically laid out your 2 options. With the rotary controls and the scoshe panel, installation IS fairly straightforward. The hardest part is wiring up the defogger.

i say that running an amp is exceptionally easy but thats me. that almost your best bet if you ask me but bear in mind unless you have rca hookups on your speakers on the back its gonna be hard to get the signal to the amp which means... no go. if you have any questions just ask.