Your "tire pros" are wrong. All the Jeeps come with the same brakes and also come stock with both 16" and 17" wheels (in addition to your 18" wheels).
A VERY popular combination here is a 15" wheel and a 33 x 12.5 x 15 Goodyear DuraTrac. You can also get a similar combination in a 16" size.
Check out this thread to get you familiar with what you can do on a non-lifted Jeep:
Largest tire on stock JK? Here's your answer!
You should get tons of info there and put you down the right path with your tire/wheel choice.
Good luck and happy Jeeping. Be sure to keep us updated an what direction you go. You'll quickly find out that each option has its benefits/drawbacks, so there is no one right answer when it comes to wheels and tires.
Let us know if you have any other questions.