You can just bolt the K03s straight on. No other parts required apart from oil, filter and coolant.
It will run without a remap, but could cause some problems, overboosting, limp mode etc. I'd say minimum, £200 for turbo, then £250+ for map. So £450+ really.
To get the most from it, silicone TIP, 3" downpipe and front mount intercooler with a stage 2 map for the K03s would see the most benefits