I found it best to install the side units first and then, leaving the bolts very loose, install the cross piece. It is a very precise fit and I doubt I could have installed it as a unit. I suspect there may be slight variations between RAV4 units, depending on where they were manufactured. The holes available in my RAV4 were not exactly what was pictured in the directions. My RAV4 also does not have the front end attachments for towing as others have, and I put this down to variations in manufacturing sites. At any rate, the hitch has held up well on many trips with a heavy cargo carrier attached. One thing I would recommend is periodically checking the bolts attaching the unit to the chassis. Mine needed some retightening after the first cross-country trip. The finish on the hitch has held up well with no signs of rust. I have found that Vevor products are always well finished. Highly recommended.