You will struggle to get everything for under £2k. I reckon this will be more like a £3k inc vat and fitting.
Is that on top of a Stage 2 setup or stock?
Ideally ... LO400 setup + Stage 3 DSG Map for me
If you want a new L0400 it is €1,975, if you can get hold of a used K04 and send it off for conversion then that drops to €1,295 ( plus more shipping costs ). The GIAC map would be circa £500 unless you are already a GIAC customer and there would most likely be quite a bit off that. Then if you decide on GIAC you will require RS4 injectors as this is what their map requires. These are around £400. Then fitting on top.
So, the cheapest route would be for an existing GIAC customer using a refurbed K04 for just over £2k all in for the map, injectors, refurb turbo and fitting.
The most expensive route would be a new customer for around £3k.
An RS3 in tank pump or equivalent would be a good idea too and that would be another £400 ish.