how much do you want to spend.
205 you can get from a good remap and the cheapest mod for gains to be had.
after this it gets expensive and gains are not as cheap or as significant.
forget the 250bhp, its cheaper and easire to save up for an LCR which you can get 260bhp with a simple remap.
Everyone is different, but imo spending loads to get 250bhp out of a k03s cupra is silly when the LCR with better suspension and brakes to match is available.