'15 JEEP GRAND CHEROKEE AND TRAILER COMPATIBLE?

That's probably ok. The 8-spd can really make use of the V6 power. Expect engine specs in the 2500-30000 cruising on the highway and 5000+ accelerating and up hills. The engine won't care, but some passengers do.

If you can afford it, I highly recommend at least the V8. You'll have 50% more torque, which means it can purr along closer to 2000rpm and seldom need to exceed 3000rpm. Most people are happier with that.