Clio mk iv alloys and rear speakers

Hi was thinking about buying a new shape Clio mk iv expression plus 0.9 tce Eco .

My questions are ,can you replace the steel wheels and replace them with a set of genuine clio dynamique alloy wheels ?? . Will this invalidate the warranty and change cars v5 data ?? .

Second question is , does the car have wiring already in place to fit a set of rear speakers ??.

Thank you in advance barry