Thanks Erik_S. Yes the rollcage is thin, but it's deliberately thin. The Seven is not planned to rush at 150kph, because I don't think high speed is sought in a zombie world. Let's 50-60 would be enough to get free of a zombie crowd. But just to be secure, I'll add extra reinforcements.
About the sides, please see the update below. It's a preliminary double chainsaw. I hesitated with another mechanism : blades like the light vehicle in Unreal 2003.
Thanks pedro.malheiro and DbblGlock, I'll keep working to make it even deadlier !
So here's the update : side-mounted double chainsaw, windshield (that doesn't shield at all against wind

), seats (with copilot looking backwards), steering wheel, dashboard (but it can't be seen from this point of view)
There is little bug on the render, I forgot to fix it : the body of the low chainsaw is hidden. Please forgive me for that mistake