Can I fit LED replacement bulbs in my Mercedes E-Class?

Just wondering if you could give us some guidance on whether LED replacement headlight for a 2012 Mercedes E-Class headlight is a good choice and what would you suggest?

Is it legal to replace Halogen bulbs with LED bulbs?

I recently replaced the high and low beam bulbs with Philips Racingvisoon (Halogen) and noticed a definite improvement. I have always thought that LED bulb replacements would not be road legal in the UK...