Does it need premium or regular fuel. Please explain thoroughly, thanks.

 

Read the manual dude

 

You can see what kind of fuel is required on a sticker on the small door of the fuel tank cap.

If I remember correctly its ok with 95 octans, but, personally, I am seeing a dramatic difference when I use 100 octans gas.

 

Where are you getting 100 proof fuel?????? The local airport???? Must cost $8 a gallon. Unless you're at the racetrack, it's a waste of money. I can only find 91 at best here in the midwest. I use E10 it is 90 and had no issues and 32 hwy mpg with a 1.8t quattro tip.

 

I live in Greece and over here we have two options: 95 octans or 100 octans. 95 costs about $0.71/lt and 100 costs about 0.93/ lt

Have a look at the following photo of my local gas station (old prices and in euros)

 

91 octane is what the suggested label says on the gas door. You can run midgrade 89 if you want. I have noticed running premium I get a few more miles per gallon than 89.

 

if u run regular ur car will die

 

It's kinda funny that there's this widespread misconception that running a higher octane will actually improve your performance. Fact of the matter is, that if your engine doesn't knock, then there's no need to use a higher octane at all. People just make themselves think that it's better. The only reason higher octane is used, is so that the ignition temperature is different and autoignition doesn't occur. If autoignition isn't happening, then there's no need to use a higher octane, it's not like theres more energy in 91 octane as opposed to 89.

 

Higher octane fuel only serves a purpose if you have software upgrades to the ECU to apply it.
In other words, the stock ECU will only bump timing so far under the assumption that you would never be putting that high octane of fuel in the car (greater than 91 for stock).
So, you waste money and are having psychological increases to performance, not actual, if you use higher than recommended without software to support it.
Now, if you are running REVO with SPS3, or running race files on the other chips, then you'll see gains, because then the ECU assumes you are running higher octane because you "told" it you are, and it bumps timing accordingly. Now, the ECU also has correction factors where it will bump down timing if it senses problems. But that isn't a failsafe.
On a stock car, however, I would not run less than the recommended 91. Detonation/knocking is not always "heard". The extra few bucks on the fill up will be worth it to feel safe. If you're worried about $3 extra per fill up, then you need to buy a Scion or something.
Also, remember that octane can be guaged differently in different parts of the world. Europe's 100 may be US 92 in some places. Even from coast to coast in the states, the same octane rating can actually be different. West coast fuel is junk. We can still get true 93 and 94 on the east coast, luckily.
The best way to determine is to data log with VAG COM and see what the correction factors are for timing modules.