Planning to add nav system to my car, I went to the dealer and I asked my advisor about it and he gave an estimate of 5.000 !!!!! he said because what is involve in the process, re-wiring the all car because it does not come pre-wire for nav system, new console and the actual nav system, is this correct? I was thinking purchase the new nav and plug in it but with 5.000 I sale my car and get another with nav!!! any subjections? and also the factory nav come with bluetooth