If it starts hard look at glow plugs and relay. Change oil RELIGIOUSLY, these pigs will be unhappy with dirty oil. Get a good intake , look up Tamar /6637 Donaldson filter . Afe and SB make good ones also. Stay away from KN.
A exhaust is a must.
Ts 6position tuner tuned by one of the vendors here ( gearhead , beans , php etc.) Or nothing .
Get a set of gauges , boost and exhaust temp .
Maintenance is key
Smoked a bit
Turbo lit
That was it