Might I suggest living with the car for a few months before deciding whether alloy wheels are really going to improve anything?
Forgive me if I'm reading you wrong, but there's a tendency these days (for young drivers especially) to write off original steel wheels as naff, when they're actually a part of the car's character and look a lot better than any after-market alloy wheels ever will. If you want your car to look cool, it's a P6 so already does! Added bling won't improve on the original.
Right, where did I put my pipe and slippers?