hi, i would imagine the parts would not cost more than perhaps 2 or 3 hundred quid. Euro are cool, i think they would even do an engine rebuild kit comprising gaskets, rings(poss pistons)big end, little end,valveguides,seals and a few other odd and sods. the benefits are, you will have a brand spanking new motor that would have to be driven v carefully for a few hundred miles, but you could rest in peace knowing its gonna be a good one. see, if its smoking a bit i would say its done a lot of hard miles and could do with the head rebuilding and the rings replacing at least(don't get me wrong your motor could go on for another 20000 miles with no problemswithout any repairs) . If youve got the head off its little more effort to get the barrels off and do the big/little ends while you do the rings. If youve got a decent mechanic it shouldnt take more than 3 or 4 days at the most.