Comparing a X5 to a GL isn't exactly apples to apples. I have both a E70 and a a brand new GL that is less than 3 weeks old. The GL is more like an escalade in terms of size, comfort, performance and technology. If you like the feeling of driving a Heavy SUV, then get GL. If you like the performance and feeling of a sedan but want to keep the utility of a SUV then go with the X5.

As for the noise differences from the interiors of both vehicles, the X5 sits you up closer to the window so that is why you probably why it could be noiser than in a GL but I can assure you that the difference is minimal.

Both are excellent vehicles that so far seem to maintain the quality of vehicles manufactured in Europe.

The thing I hate about the GL is the stupid shift lever which located on the steering column and is literally the size of a disposable cigarette lighter. Also when compared to the X5, the technology and user controls in the GL seem privative in comparison and closely resembles to those you would find in late model american vehicles.