4AWG is fine. Basic Car Audio Electronics has all kinds of useful information including calculators for wiring, etc.

 

Thanks for your help I really appreciate it. Hope to put together a picture time line of the job on here it might help someone as I have learned a shed load trawling some forums this last two weeks and help from folk like you has been great.

 

The list grows just ordered db461 polls for the headrest. Will have to make a mount though.