When I see a rebuild that replaces that much of the car - I wonder just how well the car is put back together. I would expect the "technician" to be very careful about his panel placement, welds, etc - but is the car still "square"?
NASCAR teams seem to have "flat tables" - spend a lot of time making sure everything stays where it should be. I even remember reading an article, a few years back, where they took a new Ferrari coupe, and made into a convertible.
First they supported the car, measured from various points to ground - then removed the top. Then re-measured everything. Where it sagged, they installed needed bracing, support to bring the car back to true. Starting out with so little of the original car, I wonder how/if he took that much care?
I don't think asking this question is being too nit-picking, even though it aint my car; 'cause I often hear guys who have done frame off, rotisserie restores, find that when they get the whole car back together - the front and rear glass (windshields) don't fit ... they have to fudge them in with loads of sealer or fiddle with shimming the frame. With a unibody car, it has to be even worse?
Even factory cars, where they usually take a sedan and turn it into a convertible usually have extra supports and bracing put in to keep doors from sagging, slow down body flex that usually kicks in after a few years on the road, kids swinging on the door - all the real world crap
I ran into a smaller, but similar problem when I installed an engine. I used a level to make sure the mounts and motor were in right. Unfortunately... I eye balled the ground in my driveway. I figured the slope was "close enough", used some Kentucky windage to compensate. Once I got everything together ... I noticed that engine had an obvious slope to the drivers side. It didn't hurt anything, but it went a long way to explain why the headers were such a bear to install. I was kinda' lucky, it wasn't too hard to put shims in to make up the worst part of the difference. For me, it was another Lesson learned - the hard way.