What to use for Leveling my 2015?

I'm new to this but I have a question about what to use to level my 2015 TRD sport 4x4 double cab long bed. I don't want to adjust any suspension. It sits at 37.5" from the ground in the back and 35" in the front. I was told it would make the ride super rough or not change it much at all besides a bit stiffer.
I have about 33" wheels/tires already on it. My truck is new and I really don't want to $&)@ it up. Please let me know any opinions. Thanks.

 

All leveling kits involve changing or adding parts to the suspension. The simplest would be to upgrade your front shocks and coils. It's relatively inexpensive and actually rides better than stock. You're new here, spend some time searching bilstein 5100 options.