The early 3.5 with AGG lump in it is very much the same as the Mk3 but the later one is not.
There are similarities between the 2 but the 01 model 2 litre has the ABA engine which was never available in the MK3 or MK4 in the UK.
This makes for a lot of changes,especially to the electrics side.
Best option may be to get a manual for the late mk3 but the US version as they had the ABA in them not the AGG.