I fitted one of those to cure the engine hesitation around 1800-2000rpm, and it really made the difference. However, approx. 2 weeks after it was fitted, the Emissions Management Light came on.
Ended up putting the original gasket back in, and reduced the EGR to the minimum via VCDS. The hesitation is cured 90% I would say, and it does not throw the EML.
Either way, it is well worth it, as it makes the driving much better.