I think it's not really worth moding the 1.0 tsi if we are talking horse power. It's original power is 90hp from the vw polo but Seat upped it to 115hp. I got 2017 model
ibiza and the dsg box have failed on me twice both leaving me in middle of traffic that I had to call Tow truck. Luckily I had warranty because they replaced my dsg mechatronic two times. After first time replacement it ran fine 4 months and died again. On replacement parts you get 1 year warranty so I was lucky to got it replaced again for free. Don't modify this engine because the transmission isn't built to last.