I have a really good wide-screen Garmin GPS unit. Is it worth it for me to order Nav on a B8? I understand it comes with other features, but will it diminish the value of the car much if I don't order Nav?

To me it's like ordering a car with no power seats. Sure, they're nice to have, but it probably won't affect your enjoyment of the car much (in fact, after having my B6 driver's seat motor break twice, at a cost of $950 each time to repair) I wish my car had manual seats!)
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Navigation is worth it, but the portable units offer a much better value.

Besides, it is my understanding that Audi will be releasing a new HD based version in the new Q5 that will make the current version somewhat obsolete.

IMHO having a 5 year old computer in a car doesn't do much for resale value...

For me, Navi is worth it. I don't want to fuss with mounting, removing, remounting a portable navigation unit. Plus, it doesn't do anything for the interior aesthetics of the car.

Things like where to mount? How to hide the wires? Etc. The built-in unit just does away with that.

I've read that cars with built-in navigation units don't do any better with depreciation than those without, with some doing worse.

Regarding power seats, they are nice to haves. But, I think power seats with memory are more than nice to have because it makes it so much easier to share a car with your spouse. :)

The things are updating so fast now, the 3 year Garmin we just got rid of was obsolete and I can get excellent routing now from either my phone or the new $220 Garmin. Personally, I think in-car systems as they exist today at $1,500 - $2,000 extra are now extinct. I'd much rather put that money towards something more cost effective. $0.02, YMMV.

I wouldn't waste my money on one of their Nav units again. It's user interface is appallingly bad compared to that of Garmin's or other 3rd-party venders.

Resale value isn't a concern for me since I'll usually keep my cars until the wheels fall off; or until the resale value equals any impending repairs on the car.

You can buy a $100 cell phone with very nice GPS build in to it. It works and would get you to your destination if/when you get lost.
Why would anyone drop $2000+ on these Factory NAVS makes me wanna go POSTAL!!!
In 6months it will be obsolete, just like the PC you're using at this moment, or your pic camera...etc. With that said, save the $2K+ for MODS!!!

I will likely mount my Garmin Nuvi on the windshield above my built-in nav and use it for traffic - a missing component in the Audi nav.
Oh yeah, I almost forget about the back up camera that is part of the nav package. Another cool, overpriced toy. Gotta have it too.

Others may take a different view of course.

"I understand it comes with other features, but will it diminish the value of the car much if I don't order Nav?"

probably not more than $2500

I own a Garmin 760 that I mount with a Proclips vent mount and it's wonderful.

I live in a rural area so there is FM bandwidth available, giving me bluetooth telephone and sd card Mp3 playback through my stereo.

There are many many advantages to having a quality portable GPS. The feature sets GUI have improved well above even the best OEM nav units. And the prices have come way down making them a no brainer.

There are a few notable downsides though.

1. Even with the best mounts available, you don't get the perfectly integrated look and fucntionality of OEM.

2. Their life expectancy can be spotty. My Garmin Nuvi 660 just died about a month ago after 20 months.

3. No matter how careful you are, eventually, some crackhead is going to think about stealing your portable GPS. My first GPS was a Garmin SP340 that was stolen. Replacing a, then, $400 GPS sucks. Digging out shards of safety glass embedded in your wood trim and leather sucks WAY more.

So... In summary....

I'm a huge advocate of Garmin GPS units.

They are a fantastic alternative to any OEM nav.

There have been times where I needed to utilize my GPSs in other vehicles that I would not have been able to do had I gotten a NavPlus.

All that said.....

In the last 28 months, I've bought three garmin units.

SP 340- paid $400 (stolen in 5 months)
Nuvi 660- paid $850 at launch (died in 20 months)
Nuvi 760- paid $375

For less money I could have retrofitted NavPlus unit and bluetooth and my interior would be in better shape.

I'm not going to buy a '09 A4. I'm waiting until '10 and, if the new upgraded MMI Nav that's supposed to show up in the Q5 is available at the current NAV price, I'll be buying it.

On a BMW motorcycle forum I belong to, quite a few members have had touch screens delaminate(some after 5-6 years) and Garmin has always repaired/replaced the units free of charge.

power supply pin on the back of the unit. It wasn't a manufacturer's defect.

Even if it could have been repaired, it would have cost more than the price of the 760 which is a superior unit.

... and if it's inconvenient to take it with me, I lock it up in the trunk.
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windshield ring from a removed suction mount or any visible mount or indicator that you own a GPS on your car.

Granted, a crackhead will go for a clearly visible GPS unit over a car that just looks like it usually has one installed but it doesn't deter them completely.

To me, the only thing worse than getting your window smashed and having your GPS stolen is having your window smashed to look for a GPS when it wasn't even in the car.

And yes... that happens ALOT.