Car appreciation... the aesthetics, the engineering, etc

Hey I need some advice. I've just brought my Mum a Mini Cooper (2004) for her 60th Birthday which is March next year. However my mum is a petrol head and i'd like to have it pumped up similar to what Brabus (www.brabus.com) do, only UK based. Im not really knowledgable regarding the current modification scene so can anyone recommend a suitable company. The closer to London the better.

http://www.ac-schnitzer.de/en/mini/