I tried it inside my trunk and it was quite spotty.
I have tried mounting it upside down in the trunk and I could not get that to work, either. It may work on your dashboard, though.
I had a Delphi XM tuner in my e46 and I did like the way orange text looked in the car at night. I do like a cleaner look than what you have here, but I guess this install saves you from purchasing two car kits.