Hi everyone firstly this is a great place of knowledge and love looking through all the posts on here .
Right I have edc15 suite as tuning software and use mpps to put files on to my 115bhp mk4 golf I've tried a few different maps I've played with and so far I've improved mpg from 40. 5 to 45.5 can anyone give me advise on how to get the balance between power abd economy?

Hm power on diesel engines is major gained by increasing the injected fuel.
You wont drive economic if you request your power on the tuned engine.

You may get a leaner midrange because of boost pressure and some
tuners change the pre injection timings which will result in a noisier engine but
could reduce fuel consumption a little bit.

Conclusion on diesel engines:

If you wanna have more power you will need more fuel using it resuling in higher
consumtion.

If you wanna have an economic car you have to decrease power and lower fuel consumption.
:P

As a new member, can i ask some without making a new post?

Many chip-shops offer:

Stage 1 - no power increase, but 1l/100km decrease
Stage 2 - slightly power increase and 0.5 liters economy
Stage 3 - max power but no economy

Is the fuel economy from the increased power or its result of the fine pre-injection timing changes. What is the relation between this fuel economy and the CO2 emissions?

Thank you so much!