TD42T performance additions - where's the sweet spot?

[Winnie]

Thanks guys. One shop I spoke to offer a 160-180rwkw offering with chip, custom pump/injectors, turbo, CC intercooler, aluminium radiator and tuning for $12k which is a lot of coin. So it got me wondering what each bit adds and where the sweet spot is, particularly for a touring rig where economy and reliability are key variables.

I spent less than a third of that, new turbo and intercooler, and am getting 120kw with 12L/100km fuel economy.