Don't diy

I read with interest your comments to Ray Exell. I too am rebuilding a car, a VK Calais with a fuel-injected six for my daughter and plan to convert it to unleaded. I will be having the cylinder head reconfigured to take unleaded fuel, but what are your views on fitting a catalytic converter? I believe every car that runs unleaded should at least use a catalytic converter as the unleaded exhaust gases are worse for the environment.