OK, i have a 2006 g35 6mt. What id like to do is add a 4 channel amplifier to the stock radio. Im going to use high level inputs to the amp from the radio.....if i can ever find the color codes for all the speakers. Im lazy and dont want to go through the of taking all the door panels off to get the correct wire colors and besides id probable break clips and the like. the amp will be used to add a sub bridged. Next question....how are the tweeters protected from low freqs? does the radio filter them or are there resistors at the speakers them selves. any help or diffrent set ups would be very helpful. i have a decent knowledge of 12v audio so terms like ohms and bridged arnt lost on me so thanx again.