Have just bought myself a blaupunkt 400w amp. Can anyone tell me what "bridging the channels" means and how to do it. I heard someone say that you bridge two channels to power the sub, Is that correct?

you basically use the + from one channel and the - from another to increase the power going to the speaker/s. not all amps will be happy to do this, and it is normally on the speaker terminals what connections to do/use.

Cheers. I hope i can fit it. someone has removed the stereo connectors and left a birds nest of wires behind. Is there a guide that tells you what wire does what as i might want to change the head unit soon.