Mk4 1.8T chip (k03s) Vs A3 1.8T Chip (k04).

Mk4 with big frontal cooler. A3 doesn't have.

[MrSagerific]

This is a live example of the torque spike problem that you get from swapping a k04 to a 1.8t. While the k04 does spool faster it doesn’t not provide the same airflow across the power band and gives better torque at low end. You can actually make more horse power at higher RPMs with the stock Ko3S but not as much torque. And this is a real world example of this. The k04 1.8t provided more torque for the hit, but the ko3 1.8t was able to pull harder once they were rolling. This is why you should save your money and do a t3/t4 hybrid conversion, your engine will also last longer than a k04 swap.

[stevecook]

They are exactly the same car and engine underneath

[rmfungaro]

turbo k03s better at low rpm
turbo k04 bigger rotor, better at high rpm.