gbs mass produce kits that bolt together where as the roadster is more total self build or buy in parts with only one full kit supplier
almost two opersit ends of the kitcar market realy
best place to ask would be locostbuilders as people could be a bit bias in here
i would ask your self what experance/skills you have, what tooling you have and the quility of finished car and would you see the project trough.
the roadster isnt so cheap if you have to buy loads of tools a good welder and have to pay people to the bits you cant but is if you have loads of skills and can do almost everything youself
