Will a normal boost gauge work or will I need a Different one for a tdi? What sort of psi/bar will I need?

Car will be getting remapped soon

You don't need a gauge specific for a diesel, I've just used a regular auto gauge one and it works fine, something up to 30psi will be fine

So would 2bar be to low? What sort of bar will a Standard Fabia Vrs do?

I think a stock one is about 1.3 bar. My old hybrid boosted at 1.6 bar @206bhp/330lbs/ft.