Will towing a 23' toy hauler destroy a 2007 Titan Crew Cab WITHOUT a towing package?

Depending on engine and transmission, and if the vehicle is not equipped with an aftermarket transmission cooler, you may have some problems.

according to the Nissan site, your truck is not recommend to do this, if you dont have the "tow package", according to Nissan, you will not be covered under warranty. My buddy found that out with his Nissan pick up (small one), he towed a snowmobile, and his tranny went, they seen the hitch and wiring and voided his warranty. I would ask the dealer what you need to do to the truck so you dont void the warranty, with out the tow pkg, you dont have a heavy duty brakes/rad/tranny cooler, your rear diff is not made to tow a heavy load and your suspension is not set to tow. Just trying to help, so you dont get screwed if something brakes, best of luck though

You do not have to have a tow package to tow with a Titan Crew Cab, check out http://www.nissanusa.com/titan/specifications-king-cab.html, under capacities it specifically states that you can tow between 6400 and 7400 pounds depending on which Titan you have. So if you do have a trailer hitch on your vehicle, but no tow package they would have to prove that you are pulling more than that.

By the way, the smaller truck has to have the tow package, at least as far as what I see from Nissan.

there are no differences with the engine and tranny, they come equipped with the same motor and tranny, no matter if you get the offroad package, tow package, texas package, even the low end xe has the same motor, only difference is tranny with 2wd or 4wd