I have to say, I'm not a Jetta owner, but I did stay at a Holiday Inn Express last night.™
My dealer had no GLIs to test drive, and if they had the GLI Fahrenheit- I would be driving something bright yellow. So I have a 4dr GTI.
So when it comes down to "chips", a few things:
It's not an actual chip, it's a software upgrade to your engine management software.
You also have some great choices:
Revo, APR, GIAC, Neuspeed(?) and a few others.
Some vendors offer a 5 hour "preview" of their software.
What can go wrong with "chipping"? Some folks have reported having their diverter valve (DV) blow or leak after being chipped. It doesn't happen all the time and it depends on what version of DV is in your car. DVs (vs. BOV s) are a whole 'nother topic.
But as far as best bang for your buck to make the 2.0FSI faster, consider "chipping" it. 8)