For what it's worth, I've pulled my 3400# (dry) boat plus trailer/gear/gas with a 2005 Titan w/ the 5.6L V8. I'd say I was close to 5500# fully loaded on that trip. I pulled it with a Titan and the thing really struggled holding speed with a headwind. I'm talking 70mph speed... it would sit at 65, but the thing really struggled up hills and the gas mileage was horrible (8-10mpg). I'd look at other options unless you're waiting for the Titan loaded with the new cummins diesel. Handling wise it was fine. Didn't ever feel the boat would push it around, but my boat is much smaller than an x45. Mine sits on a single axle boatmate trailer, which pulls great also. This was over a 20 hour round trip drive from KC to northern MN and back.