Ive just got a mk3 ghia 2.0 tdci 2003 for £200, to use as a work hack,not knowing anything about these engines i was wondering if any of you could recommend anything i should do to improve it and future proof any bits that are common for giving issue,she smokes a bit when 1st started,i was thinking maybe has a leaky injector?is that a thing on these?

its meant to be 130bhp but feels about 100 or less at the minute,is there anything i should be looking at that could sort that easily?