I love my AWD. The only things I can think of to consider are your plans with it in the long run. For example, if you plan to lower it, you may end up with the "wobble" . I did air and haven't seen it but it is an issue with a lot of people. And also choice in wheels is another issue for some. I have staggered wheels but you have to be very careful to make sure you have the same overall rolling diameter or you can really mess up the drivetrain. But I have done both correctly and very happy with my choice. Good luck with it man!!
patakijv, I have a 2008 GS350 AWD and love it. The only issue I had were the brakes early on that they changed with the recall. I currently have 111,000 miles on it and the only thing I changed were the tires once (continental extremecontact DWS) which I love and the brake pads (doing today). Had the rear caliper sieze but no biggie to fix. Other than those two things, I have done nothing to the car. Just use synthetic every 7k miles and that's it. Love the car.
I am considering buying a used 3rd generation (may also consider 2nd gen) 300 / 350 and wanted to get some input from the club members' experience on the topic of AWD.
Do the models with AWD present any issues to be concerned about before purchase? i.e. should check something specific first Check front CV boots, other than that... nope.
Are there significant maintenance, cost or reliability issues to be aware of while owning? You have 2 more axles that "potentially" could go bad. This is not common whatsoever thus far.
Are there certain years that had the AWD to avoid for some reason? Not that I've ever seen
How much/does the AWD degrade regular driving performance and mileage? maybe by 1-2 MPG depending on your driving habits. Performance? Equal or better grip in all situations, but acceleration is ever so slightly slower in higher gears (more drag on powertrain... think 50 to 80mph acceleration) You would only notice this if you were drag racing an equivalent GS with rear wheel drive.
Is the use of the AWD noticeably beneficial, at all?, when needed? The GS300 has 0-60 times that are basically identical in the dry... the GS350 AWD has a faster 0-60 time than RWD. Other than that, the AWD has a 30/70 (front/rear) torque split most of the time. The GS300 AWD is the lightest/most grip/best balanced combo, but not the quickest. The GS350 AWD has more power, is faster, but does weigh considerably more. (the GS300 AWD weighs roughly the same as a GS350 RWD)
The AWD is nice. If you don't plan on lowering the car, I'd look for an AWD before just a RWD... but then again I live in Indiana where we have icy/slick/snowy roads for at least one season out of the year.