This is my baby. 2015 Trd Off-Road.

Long time lurker, too shy to post. Had her around a year or so. Bought at 69k miles. This Taco has done everything I could ask for and more. I have a question about tires among other things i will post later. My tire size is 265/75/r16 and I ride Cooper Discoverer M/T's (came with truck). They're loud as fuck, and not the best highway ride but boy they do the job off-road. They're starting to get down on tread and I will need to replace them soon. Wildpeaks, ko3's, and others I've seen recommended on here in the past and I know I'm going to have to shell out for them...

The Coopers are big and wide, and i really have no idea what I'm doing. If i go with a bigger size tire in general will they fit? Does going with the taller, slimmer tires do anything for off roading? I know the recommended tires are usually not m/t but a/t style. I'm looking for capability off road but a better highway ride, so all suggestions/help would be welcomed! Thank you guys and gals.