The 4.4L V8 in the S2 and S3 had the same engine and it shows as London ULEZ Compliant. Euro 5 as Peter mentions.
The S1 had a different variation of the 4.4 V8 (single VANOS cam) and using a numberplate off the interweb (shows 2001) it also shows Euro 5
The last MOT Emissions Test shows the engine in Tarka passes all the tests by a massive margin. All it really puts out is CO2 and water.
I suspect at high revs it is rather different, but that condition is not tested!
