I what to change my halogen headlight bulbs, sidelights and DRL lights on my car to make it look more interesting, I was thinking maybe LED'S but I don't want to create faults?

You asked a very similar question here: http://www.briskoda.net/forums/topic/415879-led-bulbs-in-2010-facelift-octavia/

 

DRL and sidelights should be fine, just use quality LED's and be prepared to add load resistors or find someone with the right knowledge/tools to code out the warnings depending on your BCM, this isn't possible with VCDS. I use:

- Morimoto XB LED 1156

- Philips X-treme Vision LED 360 T10

 

Don't bother with LED H7 replacements, they are not a good substitute for halogen bulbs as the beam pattern under the cutoff will be terrible. Use a quality halogen bulb such a Osram Night Breaker Unlimited or Philips XtremeVision. If you want it to look whiter at the expense of output, you can try the Osram Cool Blue Intense or Philips WhiteVision.

The Octavia headlights are designed to focus light from filament bulbs that produce their light in a very small area of the filament.  LEDs don't produce their light this way, and where they are fitted OEM, their reflectors or lenses are specifically designed to accommodate the way they produce light spread over a bigger area.