The gains are only the top part (non sweet spot) of the rpm spectrum? This is where AMG at least gives you tangible measurable sweet spot gains.
As for the suspension I like the improvements- 20% is lot for spring and dampener rates along with better steering.
Its only money- Id pay it LOL
2016 BMW M5 Alpine White
2016 AMG GTS Edition 1 Selenite Grey
2015 Lamborghini Huracan Bianco Canpus (Matte OEM)
2015 Bentley GT3R Glacier White
2012 Mercedes Benz C63 AMG Black Series Obsidian Black