Being the question is about a TD42Ti you won't be ale to chip it. A 3" mandrel bent straight through exhaust including the dump pipe and a decent Dyno tune will set you back about $1000 if you shop around. You will drive in with about 65rwkw and drive out with 95 to 100rwkw.
You will need a variable boost controller too and I recommend a Pyro Gauge too so add another $500 for that but a great place to start.
Once the above is done you have a very good starting platform that will work great and be ready for any future mods you want. Hi flow the turbo for $1800, replace the turbo for $2500. You already have an 11mm pump so pump upgrades should be down the list.
Have fun. Every mod gets a grin![]()