Hi all

Im new to the forums
Just got myself a secondhand mk6 golf tdi and would like to ask about tuning options.
From what ive read theres 2 types of tuning.

1) Flash (CPU/Bluefin/etc)
2) Tune box/piggyback (Dtuk/chipexpress)

Im more towards a tune box (Dtuk) as its about half the price of a custom tune.

However, from researching (forums) it seems a Tune box would perform 90-95% of a custom tune and consumes more fuel. But on Dtuk they claim up to 20% more fuel efficient.

In the real world is that true?
Any reviews?

Thanks
Mark