I just got back from a 1000 mile trip with my new cargo box - I bought a Sportrack SR1002 rack and Yakima Rocket Box Pro 12 cargo box for my 2014 Plug-in Prius. The rack was inexpensive at $145 and didn't require any add-ons - I was annoyed at Thule and Yakima bars where you need to buy the ends, then buy a "fit kit", then pick the bars you want. The manual included settings for most cars and went on in 10 minutes with a little bit of trial and error. The box didn't require any assembly, unlike the cheaper Thule box I looked at, and was very solid. It opens on either side, which made mounting easy. To mount, you loosen the mounts on the inside of the box, adjust them to fit your bars and tighten them down - it took me about 5 minutes, and was a little clumsy to get onto the rack but could do it myself in a pinch. The key can't be removed while the box is unlocked, FYI. I was able to get one big suitcase, a full-sized carry-on bag and a kids roller carry-on bag into the box, which made packing the rest of the car for 2 adults, 2 kids and 5 days leisurely. I didn't have to wedge the back so tightly that you couldn't get to anything, and the passenger compartment was luggage free. I took the luggage cover off and we could reach back to the cooler for drinks while on the road. I think I might trade up to the larger size and mount a donut spare tire in there for long trips. Wind noise was negligible with just the rack, and became noticeable with the box only when going over 70 mph. Gas mileage? I get 46-48 MPG freeway at home; switching to Michelin Defender tires cost ~ 2 mpg compared to the OEM LRR tires. Much better handling and *much* longer lasting, but that's another thread. I got 41-42 mpg with the 4 people and the box, doing 70+ on I-5 in California, up the Grapevine. Not too shabby.
Looks like a good fit. Any updates on this box? Thinking of upgrading from a Thule Excursion that's starting to fall apart.
So glad I found this...looking at Yakima/Thule racks right now. I definitely see the frustration. Not wanting to spend $500 on just a rack for my snowboards.