Friend of mine had a larger intercooler fitted. Said it made b!!!!! all difference.
Then we said Dave have you turned the fuel up?
The result was a good bit more power and little difference to the economy because you don't have to change down, it'll just cruise in top with a lot less effort.
I'm planning to turn the fuel up a smidgin on my Tdi 200, it's at factory settings at the moment.
No smoke= not enough power.
It's a trade off. Don't make the MOT tester too unhappy but get some extra power.