Mhh I have no expirience with curved screens. The projector solution is quiet new for me and this is my first try with this kind of setup.
A big disadvantage could be the needed additional software for a curved screen. You need to warp the image that it fits to the curved radius. The softwares i know are quiet expensive regarding the complete hardware costs. + someone will have to proove if they add a lag or will reduce the image quality.
Perhaps it could be better to use 3 projectors for a curved screen. But if doing this you will need to blend and warp the image with a software. An advantag if doing this way would be the better resolution. Perhaps I would test the projectors in portrait mode?
As said before if you could realise it with your rig design a full hd resolution would be way better than my setup. 720p native at a distance of 55cm is the absolut limit (the single pixels are visible if you focus but not noticable while driving).
Perhaps there will be cheap 4k short throw projectors the next years
this would be a upgrade reason for me.
In summary i think a curved screen could be a even better option but there are many things to check first and the price will increase.