What Stage 1 tune

So i want to go stage 1 on my 2020 gti dsg. Do I need to tune the engine and the transmission? If so what tune should I go with? What's a good price? And what should I expect when it comes to performance and economy? I'm new to the gti and all my other cars have been manuel so point me in a good direction. Thanks. My last car was a 2014 tdi golf stage 2