Trying to contribute to this, as usually 1.4 do not get much attention:
Until now, I have tried DTUK tuning box, MTM m-cantronic and Superchips Bluefin and:
-dtuk was aggressive, the engine operation was not at all smooth, especially at 4<->2 cylinder operation transition. Removed quickly.
-MTM brought crazy performance and smooth-as-stock operation, BUT, resulted to 2 faulty turbochargers, one after 16.000km and one after 1.000. Thank god it was not detected by the dealer and warranty was not compromised.
-Superchips was the most short-lived. Having the previous experience, I monitored via vcds the max pressures and removed it when I saw 1.5 bar.
My advice would be to stay away from tuning this variant of the EA211 engine, if you do not intend to upgrade your turbocharger. I think a greek company (rtmg) offers a hybrid turbocharger for up to 240hp.