The OEM/stock wiring and load capacities are rated for 42W - that's the stock fog lights' wattage. Even if you were to replace the existing stock fogs, I wouldn't install 55W lights without a relay.
That being said, if you are looking for brighter fogs, I would consider an HID conversion of the fog lights. I purchased them from DDM Tuning and am very pleased. No need for new wiring either since they only draw 35W, but put out more than 70W! They are awesome and you can purchase the bulbs in a variety of color temperatures - I got the 3000K since I want less glare in fog, rain, snow, etc. and use them exclusively for that purpose.
Also, the conversion is fairly inexpensive and is plug and play. It took longer to bundle the wires neatly than it did to install the new bulbs. Just be sure to purchase the correct size and type. Also, there are differences between 2007/8/9 and 2010/11 models.
2018 JL Rubicon Unlimited, 6-speed, White
1985 CJ-7, 4-speed, 258 I-6, 3" Springs, 33" BFG AT, Gunmental Gray