I'm confused! If I replace the head unit with an aftermarket single stack one, replace the amp and speakers, this will messup my heat/AC? If I'm replacing everything, why is it such a PITA? I'm mech. inclined, not elect. so please make your answers REALLY simple (plus being old)

 

You're not really messing up the AC/heat. Since the AC controller is attached to the factory radio, you will need to buy a new AC controller that is not attached from Infiniti/Nissan.
The whole install is not a PITA unless you'd rather have someone to do the install. Just read Wrathernaut's guide carefully and other stickies & you'll be fine..

 

If you go aftermarket, then the dash kit you buy (Metra or JDM) will come with the AC/Heat controller that will plug into your factory harness.

 

So if I keep the stock head unit, replace the amp and all speakers I should be OK? No problems with the AC etc?

 

yes, you can add a line output converter and keep your factory radio while adding amps

no need to mess with your AC controls

 

If you have a "premium" bose sound system, you don't need line output converters, you need an amplifier that accepts differential-balanced inputs (JL Audio amplifiers are the most readily available that do this) or a converter like the MTX REQ to pair with an amplifier, however, the cost of the MTX-REQ + a good amp is going to be more work and probably more money than just getting a JL Audio amp.

If you do not have a bose system, you can still go without a line output converter, if the amp you use has speaker-level inputs (90% of them do).

Some people thing that you need LOC to go from speaker wires to RCA cables. You don't. You just cut a RCA cable in half and connect the wires up. (twisted pair being the easiest, since the wires are separated already.)

 

False on G35's, you have to buy the AC unit seperately.

 

They're separate parts, yes, but most sell them together.

 

my g35 just started making a popping noise and was told the amps are bad. does anyone have any suggestions as to whether i should replace the whole system or just the amps?

 

Whole system. The factory stereos fail a lot more than the amp, so you might as well not deal with the problems associated with combining the Bose headunit with an aftermarket amplifier.

 

What brand would you recommend if I change the whole system. Its been a while I heard sound from my car? Thanks

 

Depends entirely on your budget and what kind of music you listen to.

 

Not trying to be a jerk or wiseazz, but that question has always puzzled me. I guess it's just a lack of experience with different manufacturers. Most of it depends on a person's budget, and the 2nd is what features are important to you. IOW, what are you looking for it to do and at what price?