Important Note:

If there is not a lambda sensor currently fitted, your ECU Lambda details will be disabled, therefore the ECU will have to be returned to SBD Motorsport for calibration. The cost will depend on the ECU model & under certain conditions the car may be required for emission control calibration. Contact us for details.

Try and place the sensor on top of the exhaust because of the possibility it could get knocked.
If there is no room try to place it up to 90 degrees either side from the top Only place the sensor where there is at least 110mm between the manifold and any part of the chassis to allow for removal.