5 feet will be plenty, route it then chop back what you don't need. Nothing worse than coming up short.
It will need to go from roughly manifold towards strut tower avoiding turbo, down the back of the firewall, and through, theres a rubber bung half way down, push a skewer through it, if you lift the mat out of the drivers side and look at the pedals the it should be poking through :-) then up the back of dash to pillar