Hi there, firstly before you get slated buy others, try using the search button, it will give you a wealth of information on past threads on topics like these.
It all depends on your budget for starters. Most people go for a turbo swap from a ko3(standard cupra turbo) to a ko3s turbo, with supporting mods like a full turbo back exhaust, front mount intercooler and other bits and bobs you'll see about 220-240 bhp. If you have more money you can go for a ko3hybrid swap, lots of threads on that so i wont bore you with the details. Spend more and you can go for something like a garrett gt28 turbo, classified as a BT(big turbo application), this will require alot more work and money.
So its all down to your money and time, with these two things you can get just about any power you want from your car.
But the search button is your friend