You will see gains from your setup with the precat delete and a CAI, whether it's considered true stage 2 I'm not 100% sure. This would be your cheapest way to improve the performance of your car. Try someones car with a CAI if your concerned about cabin noise, they can be very loud.
A step up from this would be an aftermarket downpipe with something like a 200 cel sports cat, this would reduce the exhausts pressure drop compared to just bashing out the precat in the OEM exhaust and leaving the main cat in place (800 cel I believe). This would obviously cost an additional £400 or so but would allow the R-tech map to produce more power.
I wouldn't bother with a new intercooler at stage 2 personally, particularly if the budget is a little tight. If it were me I'd go with a Milltek downpipe, CAI and then try and find £500 ish for a Loba hpfp (possible second hand one if you can find one) and £200-£300 for a S3 intercooler and go straight to 2+ and save yourself another remap cost when you want to go to 2+ (which you will
).