Firstly, go join the "mk6 golf owners club UK" on Facebook.
Secondly, on a 1.6tdi, do not waste money modifying it. It's not fast or cool, it'll never be fast or cool. It's a car for new drivers or OAP's.
I see it's your first car, you may consider yourself a gifted driver but, and I'm being honest here, like every other new driver you are not gifted. High chance you'll have an accident in the first year and the money spent on the mods will be a waste. You'll get no performance benefit from mods on that car and all you're going to do is up your insurance stupid amounts. Also, you'll want to upgrade to a better car within a year or two, in which case, modifying that car will slow that from happening as you're spending and not saving, you're also going to really hurt the resale value of it.
Spend the first year learning to drive, because you don't really learn until after you've passed our test. Save your money and look at getting something a little better with more power. Your main aim as a new driver:
1) Don't crash
2) Build no claims
3) Save for something better
1.9tdi if you want to stay diesel, I know they can get between 200-300bhp once modified, or join the gti club like myself. Build up your no claims and learn to be a safe driver, you can be fast and safe but it takes experience.
One thing I would say is, if you're serious about cars, get yourself on a local mechanic night class or training course, start getting some tools in and look at learning to work on your own car, brakes, services etc. It'll save you a fortune down the line and will help when it comes to buying cars in the future.
Where are you located? Find a local car club and hang out with like-minded people, you'll learn a lot.