There are many things you can do to transform the Peugeot 206 into a more powerful car. Some intake modifications and suspension mods are really all that is required.
Peugeot 206 CC 1.6 109hp tuning
Citroen and Peugeot ecu tuning Marelli 48P - OldSkullTuning
1.6 HDI 16V 110BHP DV6TED4 tuning with EDC16C34
Peugeot 206 sw Tuning box 1.4 HDi, 68PS/50kW, 1398ccm
Chip Tuning Box for Peugeot 206 2.0 GTI RC 177 HP Power Performance Petrol GS2
Peugeot 206 GTI Marelli 6LP1 TunerPro xdf - OldSkullTuning
Map tuning Peugeot 207 - CKECU
Peugeot 206 S16, Tokyo Xtreme Racer Wiki
Peugeot Performance Fuel Saver Intake Kit
CR Tuningkit Anleitung engl - Autotechnik Saretz e.K.
Database of Dyno results
Peugeot 206 2.0 16v RC stage 2 - BR-Performance - Motor optimisation