Ok, turbo oil lines may or may not work. I've seen 1.6TD oil return lines dump into the oil pan, while my 1.9TD goes back into the block (somewhere). I'm not even certain of their interchangeability, but you will likely need both intake and exhaust manifolds and maybe even a different down pipe to make it work.
I have the K03 turbo in my 1.9TD. It spools from 1800 - 2400rpm where it reaches full boost at 10-11psi +/- 1 psi. However, this will be shifted up the rev range with the lower displacement of the 1.6. I'd rather skip the headache of swapping turbos and work on reducing backpressure and improving fueling.