To answer your questions:
- Could Front Aux input make installation easier or is it the same?
A feature like a front aux input shouldn't be limiting you to only three choices, it's no big deal at all to use a HU with a rear aux input. Buy a three-foot RCA-to-1/8" plug cable (you can find 'em for like $5 at radio shack) and when you're taking apart the dash to install the HU, plug the cable into your rear aux input and lead the headphone jack through an opening in the dash. I've got my cord coming out where my removable change tray is since there's enough room to lead a cable out through there. There is no added pain when it comes to the installation at all, and it really opens up your choices a lot.
- Sound with Aux input should be better than FM transmitter, right?
Absolutely. There's really no noticeable interference with an RCA input as opposed to the FM transmitter which accepts the same interference radio stations do. It's basically the difference between listening to a CD and to the radio in terms of sound quality.
- How easy is it to replace the stock Honda Stereo with Above stereos? Can I do it myself? Dont want to pay Best Buy or CC, if I dont have to. Never done something like this before. Does front/back aux make the installation any different?
I'm assuming you researched these on crutchfield? Buy from them if you'd like to install them yourself. They send you free accessories (mounting kit, wire harness, etc.), and instructions for your particular car with your HU and have great 800# tech support. If you're patient and can read directions, you can do it yourself.
- When I use Aux, it does not transfer song info, etc, right?
Nope. An RCA input only transmits audio signal, nothing else. However, Alpine makes some nice head units that have seamless iPod integration when you add their iPod adapter to your setup. Ask anyone that's got one, it's a pretty nice, easy to install setup and your HU will display the info that your iPod does. I think it's the kca-420i if I'm not mistaken. Someone else give feedback on that...
Hope those answers help, good luck.