I haven't had ours mounted yet on the Storm Trooper, but I've had a Yakima that I have been using on our Pilot for the past several years. It worked great & only dropped our milage by 1-2 mpg.I had been using a soft-sided rooftop cargo carrier for about two years on my previous vehicle, Nissan Xterra. Just tried it on the PP last week. It was kinda marginal. The Xterra had a fairing in front that really helped with aerodynamics and wind noise. On the PP, it was quite noisy at 70 MPH and I saw a 3-4 MPG drop. On both vehicles it took 30-40 minutes to get it positioned, loaded, and strapped down...which is not a fun proposition with numb hands because it's 25F outside!
Clearly, it's time to upgrade to a hard shell cargo box. The question is which one?? I have the Honda crossbars, so I should be compatible with most if not all the available offerings. I know Honda does offer the cargo box accessory which appears to be a rebranded Thule Force XT L. It's well reviewed on Amazon, but I have seen concerns about the plastic latches being fragile. I really like the look of the Thule Motion XT L in the gloss Titan (i.e. silver) with blackout trim finish. I think that would look AMAZING on my silver PP, but I'm not sure it's worth it for $750.
What are you all using or would suggest?