Well...looking here for new hot car audio/video/nav gear seems to be sort of an effort in futility and I would recommend looking elsewhere if I hadnt logged on and seen you query.
The most recent review on these units and subject is from 2007 on CNET(and that is FRICKIN' RIDICULOUS Guys!!!)
My top listing for In Dash Solutions
Kenwood DNX9140
Kenwood DNX7140
These are awesome units and will outperform most on the market...Garmin is built in so you know the interface will be consistently upgraded.
Now here's a little fun tidbit: with a few less features(nthing to cry over) JVC fresh off its new union with Kenwood has a unit that has 80-90% of the functions of the Kenwood for half the price(check Ebay and steet prices of $700!!!!
Model KW-NT1
Also Pioneer has new units but I HATE the look and function of their navigation map software...dont do it!
Good luck my friend!
Best units to use? Any pitfalls out there? Would like one that interfaces with my bluetooth phone and has front panel inputs for iPod. I am planning a professional install.
Thanks

Chowhound
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