is this the lamba sensor? my brother has just been told by Audi that his o2 sensor has gone but want nearly Ł250 to replace it! now if its what i think it is it should be easy to change but im not 100% sure.

so is it the sensor on the downpipe of the exhaust manifold? and what part is it? i think ive found it on GSF and its listed as;

https://secure.gsfcarparts.com/shop/

Part No: 930VG0780
Name: LAMBDA SENSOR FRONT OF CAT
and its about Ł90 inc vat

and the car is an 03 Audi S3.

Cheers