Yes, you can go therough the carwash. You will find out really quick if your sunroof or marker lights leak. Many have in this case. I do run mine through on occasion, but no leaks on my 06.
I have not owned an X5, but have driven them in the past. Your stopping distance will be a change for you due to size/ weight. It's not bad at all, just a little more is rewquired. The width will also be change you will quickly get used to. Use that hood handle to center yourself in your lane. It works well.
If you plan to tow (you already said you are) get the air susp. option for sure.
Also if you don't already have a GMID certificate, this will save you some cash. I'm sure if you ask nicely, someone on the board may be able to help you out.
And most important, don't bling out and Desert Sand is the best color.
