MQB injectors are completely different.
You gotta pay to play, so stump up for the proper K04 injectors and give yourself an easier life. You can get them from aftermarket suppliers for less than dealer prices, but not a lot. They are what they are and in demand and priced accordingly.
Also check with your tuner they can rescale the K03 rail pressure sensor, or insist on the K04 rail sensor. Most competent tuners can do the former, saving you some faff and money.