Has Anyone Replaced Lambda (Oxygen) Sensor on 4.2L Petrol Without Removing Manifold?

[aTOMic]

I think I need to do both "upstream" or "pre-cat" sensors. Bentley says it's necessary to remove the intake manifold. I wondered if it's possible to avoid this, since I'm a lazy American

Precious little info here or on Audiworld, band hard to search since it's variously called O2 sensor, Lambda probe, Oxygen sensor, B1S1 & B2S1, as well as HO2S and G108; but I am an eternal optimist.

TIA,
Tom