make sure your car is tip top , tyres/oil/serviced etc
then just go for it
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be prepared for possible tething troubles (PCV/DV etc) and maybe stick a bit more aside just in case (clutch if you are manual etc)
If you have a really early GTI be worth checking your cam version/follower is OK too
But most cars just remap without any issues
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and are all the better for it
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(dont forget to consider insurance costs too!)