It's turbos especially diesels that gain most & from having my previous A3 TDi 170 Quattro remapped, biggest difference was the grunt, even power across the range & removal of flat spots.
For those who've been out for a play in their Zed's at various meets during the summer, you'll know that despite the //M having all that extra power there's not too much of difference in performance between 50 & just over the 3 figure number... although after 120 be the first to hold my hand up & say it's a different story.
Save yr money is my vote on normally asperated engines