.
Neither!
Not until you've enhanced the car's handling so it works with the extra power of a remap better. Also brakes!
Then remap before wheels refurb.
Stage 1 is ok on standard brakes isn't it Robin?
It's possible to cook standard brakes without a remap, it all comes down to how you use the car and also what pads / discs you've got - fit some pagid or endless pads (assuming they do them in the GTI fitment) and you'd probably notice a much wider termperature window.
Driven enthusiastically on the road I don't find I have too many issues with the stock brakes (my car is stage 1 Revo K03), but I've little doubt that with continuous hammering they show their shortcomings. I've only found the stock brakes wanting when towing a car trailer, and once when driving very enthusiastically (on the roads surrounding the N-ring).
I'd quite fancy a lightweight 4 pot setup on the front, but I don't think I'm hard enough on the brakes to justify the cost on a road car. I've got over 50% pad left on my car after 40k miles, so generally the stock brakes aren't worked very hard in my case.
As for the OP's question.... I'd go for the remap.