Ah right sorry yes - I was thinking of the Mk4.
I've been researching these too, well more in Skoda form, for my next car. They come in 1.4t, 1.8t and 2.0t - 1.8 not to be confused with the superb mk4 1.8t, they are different engines. I don't think VAG put the 1.8t in the Golf, it was either 1.4t or 2.0t
1.8T and 1.4T cars get the dry clutch 7 speed DSG as they are lower torque. There have been some failures of this, especially in warmer countries, rectified by a change to mineral oil because synthetice caused shorts in the mechatronics unit . These made VAG do mandatory recalls of ALL affected vehicles in certain countries and optional in the UK.
Also anecdotally the dry clutch is a bit jerky and you have to learn to drive it - unlike a standard slush, or even the wet clutch DSG where you can just press and go.
There were also known problems with oil burning on early 1.4t - so much so that VAG took this engine out of the range, later 1.4ts are different. It was also a lottery with the early 1.4t as to wether you would get a burner. VAG were replacing whole engines under warranty. That said VAG have made something like 600000 of these clutches and only a relative few have gone.
I know you want a Golf but if you can find a good Skoda Fabia 1.4T VRS that has had the engine changed or is not a burner it's meant to be a belter of a little hot hatch. Or the Skoda Octavia in 1.8t Laurent and Klement trim - huge spec and decent pace and not expensive.
2.0T gets the 6 speed wet clutch DSG, in my humble opinion this is a superb gearbox. Plenty of tuning options for 2.0T also - not so much for the 1.4t or 1.8t.
Get a rare Jetta 2.0t and you'll get Golf GTI pace cheaper or newer for the same money.
With the diesels I think the CRs are not quite as sturdy as the PDs