....I agree with Hal's comments.
Personally, I would go with high efficacy halogen bulbs like the Phillips X-treme Power you mentioned or something similar like the Osram Nightbreaker Plus. I have the OEM HID's but have used both of those bulbs in other vehicles and they do make a noticeable difference.
A note on fog lamps…. Their main purpose is to illuminate the area immediately in front of and to the sides of the vehicle (to illuminate lane reflectors/markings, the edges of the roadway, etc.). Obviously, in inclement weather the distance you can see can be severely hampered and you are mostly relying on what you can see in the foreground. ….fog lights help with that. However, in a scenario where your vision is otherwise unhampered by weather, additional foreground illumination does not necessarily equal “better” lighting. In fact, more light directly in front of the car can have an opposite effect on the distance you can see at night. ….causing your pupils to constrict due to the brightness from the added light that is directly in front of you.
Having said all of that I will say that many of the OEM fog lamps on cars today are woefully inadequate in regard to performance. The Challenger is no different in that respect IMO/IME. In fact, most of the time I can barely tell they are on (yes, I am guilty of leaving mine on sometimes). Using them as auxiliary lighting for distance viewing is really a waste of time IMO. ….and adding HID’s, over-wattage bulbs, etc. to fog lamps only make matters worse (for both performance and safety of others). Personally, I would look into aux/driving lights made specifically for this purpose.
On a side note, HID kits, "hyper" white/blue/over-wattage bulbs, etc. are pet peeves of mine as well. I travel 30 miles of dark canyon roads ~3-4 times per week and the problem only seems to be getting worse (imports/domestics, family/modified cars……..it seems everyone is hopping on board the train).