I swapped out my stock speakers for 4 Sony Xplode 4 way speakers. The costs was about $80 and I am happy with them.

 

The one issue you run into off brand cheap amps is quality control. 10 years ago a dealt with a lot of those and almost 10% had a problem out of the box and another 10% crapped out within months.

A Jeep is not exactly a great listening environment. So premium high end amps, engineered for optimum sound quality, aren't really worth the money.

But driving with the top down requires much higher volumes to hear your music, and good sound a higher volumes requires higher wattage.

Most aftermarket radios that say 45x4 or 50x4 on the face are putting out around 15-17W RMS per channel. So even a true 45W RMS is a big step up.

But to get your money's worth out of high wattage premium speakers, I recommend an amp that is close in RMS output per channel to your speaker.

 

I've posted this suggestion a few times before. I've used these amps in several Jeeps and suggested them to many others. The Precision Power Phantom series is serious power for the money. There are also clones of these amps sold by Polk, NVX and a couple others. They bench test to their rated power, are fairly small and sound clean. They also come in various configuration including the PPI 900.4 that does 125w x 4 or the PPI 900.5 that does 70w x 4 plus 440w mono for the sub. They also have the PPI 1000.1 that does 1000w if you are running dual subs. Get this, they are all around $200. A steal.