I've looked hard at the Jeep Grand Cherokee as my next tow vehicle. The V6 could do it in the flatlands but would feel sluggish at times. On long uphill grades you'll be really regretting the V6. It has about 20 more HP than my Highlander's V6, but a fair bit more weight on the GC. I've had some mild regrets towing a 2700 lb TT (7' wide x 99" high) around the Rockies, and this year I traded down to a popup Aliner. If the TT you contemplate has more frontal area than the one I had, that will be an even greater factor against the V6.
That V8 is so much more capable, the fuel economy while towing will be virtually the same as the V6's, and the V8 doesn't cost much more in relation to the total price tag. For serious trailer towing, why skimp? Get an engine that will put a smile on your face when you stomp on the pedal!
