Same for early and late engines....
Stage 1 - 30 Nm (23 lbf.ft)
Stage 2 - 65 Nm (48 lbf.ft)
Stage 3 - a further 90
Just make sure you use the correct head gasket too.... will be the same thickness as the one your old engine - thickness is dependent on piston protrusion (not head)
Is the 'new' head the same age as your existing engine?? - EU2 and EU3 are not interchangeable AFAIK.
Also make sure you fit the later metal dowels.... rather than plastic.
And use new head bolts (new ones are also prelubricated - so don't use addtional oil)
I beleive there is a difference in BHP between the first TD5's and the later ones
Not really... but both EU2 and EU3 (post 2002) engines are easily tuned for more power!!!
Ian