define wise and define what you are doing with the vehicle. Also is there a cost savings? Is this your only car, and whats the use of vehicle or others you have? What is condition and mileage of both vehicles? Everybody's circumstance is different.
With that said if I had only one car the unwise purchase would be the challenger specially the fact I am married have family, live where this is snow, I like to hunt, fish, camp, and the fact I need something to haul items from time to time, so a car specially a two door car would be the last thing in the world I would buy.
Without knowing more I don't think its a wise choice to trade down per say to an older car with more mileage, you essence went from a 5 year old car with probably 50k on it to a 11 year old car with probably close to 100k on. The one caveat to that would be if you realized some cost savings in purchase price, because you wont probably see a cost savings in mpg and maint, in fact you will probably see the opposite. But if you received a large cost savings (and don't think cost per month that's a poor gauge, IM talking cost to purchase the total) and the challenger had some issues and dumping it was the best answer than maybe a wise choice.
Lastly this is not to dog you, and the SRT jeeps are cool. But with that said SRT jeeps, and other special trim SUVs and trucks IMO are large waste of money. You pay significantly more for something that maybe goes a little faster, in this case a used vehicle a faster 11 year old jeep, I just don't see it. The better purchase if you still wanted all the bells and whistles would probably the next trim level down. Then again the caveat is if you got a screaming deal, say something with low miles and cheaper than other trims out there. This basically speaking from a financial stand point, the jeep ultimately can do more than a challenger so in general is a more of a wise buy. Is this a toy or second or third car at that point its toy buying and all toys are dumb to buy really.
Then again you cant put a price on fun and everybody financial situation is different, car buying in general specially sports car is very illogical and unwise at its core.