oxygen sensors tell the computer if it is running rich/lean.

if you do not have them, the computer will just pour in extra fuel to stop any kind of detonation/backfire.



A speed density tune uses different sensors to measure load/vaccum, and changes the air/fuel based purely off that. Many guys switch over to this method when adding a turbo because it is more consistent, and doesn't rely on sensors in the air path.



For your application, stick with the front oxygens. They aren't hard to add...weld 2 bungs to headers, or use the stock manifolds.