I do a lot of long drives so I swapped my GTI for a Rocco 170 TDI (same engine as GTD).
I get around 20mpg
better overall (according to the MFD) than the GTI and I probably drive it a bit harder
I thought about Bluemotion TDI's but knew I would get bored / frustrated with it. In majority of situations the CR170 provides similar acceleration to a stock GTI, so it's not exactly slow
For me it's the perfect balance between power & economy. Plus with a remap you get 211bhp (ish) and if you remove the DPF and go stage 2, you will be on the heels of a mapped MK6 GTI