Went through this dilemma myself with my Isuzu County...
For me, an injector pump overhaul and injector nozzle replacement made a marked improvement. I also have extractors but as they were already on the vehicle when I bought it, I cannot comment on effectiveness.
I have aircon and no vents so decided against the turbo but believe it yields a marked improvement. The guys who have done it will chime in real soon.
'95 110 300TDI, F&R ARB Lockers, Twine Shower, Aux Sill Tank, Snorkel, Cargo barrier, 9 seats, swingaway wheel carrier, MadMan EMS2
'85 110 Isuzu NA 4BE1 3.6l Diesel, 0.996 LT-95, Rear Maxi (SOLD)
'76 SIII 109" Nissan ED33 5-SP Nissan GBox (SOLD)
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