I ordered the sides and the core kit, the sides came with the roofing as a one-piece "wrapper":
I got a smooth aluminum body from OK Engines, and emailed them a drawing I made of where I wanted the cuts made:
As they say, measure twice! I had to Dremel the truck cutouts a bit for additional clearance and enlarge the door window cutout in the right of the top drawing. My measurements were just a tad off and some aluminum material would be seen thru the window opening.
If I did it again I would see if OK has a shell that is smooth on the sides and ribs on the roof, the wrapper didn't have any extra material and just met the bottom edges when applied. Might not be a bad idea to have OK trim 1/16" off both side edges to make sure the wrapper covers completely (hope that makes sense!).
When I attached the wrapper I found the center of it and the centerline of the roof, so the wrapper would hang evenly down both sides, while making sure the windows all lined up.
Here's what the USP kit looked like while building:
But after a few days I ended up with a load of lumps and bumps:
I couldn't determine what adhesive to use and with the wrapper as large as it is, it made it difficult to apply to the clear core body. That's when I bought another wrapper and went to OK Engines.
I think USPs concept is great for HO and smaller, but for our larger O scale cars it may take 2 people to keep things aligned and smooth, or a slightly different design (USP team with OKE). I tired a number of different gluing methods with the core kit and sides and nothing seemed to work. With the aluminum shell, I basically coated it with super glue and hoped for the best.
Thinking back, when I ordered the core kit and sides, the sides came as a wrapper including the roof. But when I reordered the sides, I only got the sides, no roof. I contacted them and, after what seemed like a lot of heated mis-communication, got another complete wrapper. I would contact them and find out if the sides include the roof as a single "wrapper", or if you have to buy the core kit, or if you can buy separate roofing material.
The core kit includes the ends also, which are very nice. I made my own floor for the aluminum shell.
As always, the main issue with building one of these to represent a car you want is finding decals, good luck!
