[Red90]

You don't have to spend any money. Okay, you should install an EGT gauge.

Make sure timing is good.
Increase boost by shortening wastegate linkage.
Increase fueling.

Exhaust, intake, intercooler changes do very little and I see no point in spending money on any of them.

Your performance benchmark should be top speed.

 

[Red90]

I 100% agree with this except the exhaust. I have noticed serious improvement from a more free flowing exhaust mostly at top speed.

I have done carefully measured performance tests with a stock 2.5NA exhaust, open down pipe and 300TDI exhaust. There was exactly zero measurable change is maximum power. The turbo comes on boost a tiny bit (maybe 100 rpm) lower but that is all there is to get.

 

[Red90]

I stated I tested with an open downpipe. In other words no exhaust. I do R&D for a living.

 

[Red90]

The turbo restricts the exhaust much more than any exhaust is able. There are rarely gains to be made with exhaust on turbo diesels unless you go way up in turbo size and boost levels.

 

[Red90]

Don’t go by marks made by a previous owner. Look at it and understand what you are doing.