Peugeot 106 quicksilver mods

[Tabbiss]

Hi everyone, I’ve got a 106 quicksilver but I want to get more power while keeping the 1.4 engine. I’ve heard about swapping the cylinder head for a rallye head, if anyone could provide more information on this swap that would be great. Any other ideas how I make the 1.4 more powerful would be appreciated.
Thanks