HI i just started to love car audio just got a panasonic radio 50wx4 but now at half level the speakera are acting up what kind of spekear should i put on that radio à

Thnak's

What fits your car
what you can afford

50W x 4 is the peak, and those decks claim 25WRMs x4 @ 1KHZ.
What I am getting at is since you are using the deck's built in amp, you can use whatever speaker you desire. Virtually every aftermarket speaker can easily handle 25WRMS. As was mentioned, whatever fits your car and your price range will work.
Shop around and let your ears tell you what sounds best.

You can check out crutchfield.com and it should tell you the size of speakers that fit your car model/year. Though there can be occasional inaccuracies, but rare.

Insdie the glove box you will find 4 more 7mm. 2 of them are far back and are gold in color and hold a metal bare that hold the air bag cover down. the other 2 are along the lip the holds the dash pad to the dash.

More pay attention to sound quality, les on their power.