Thank you all so much for the feedback. Having checked wikipedia (!) i was able to confirm things. I dont know enough about engines to assess whether or how to improve or upgrade this one (but i did get a chance to talk to a previous owner of the car who said that he has various issues like back pressure into the expansion tank, losing water and he thought there may have been some issues with the air intake affecting the turbo (?)); so I'm going pass on this one as there is a similar vintage with an original 19J with 100K on the clock which I'll have a closer look at. thanks agan everyone.