I can't help you with what happens with the swap, but I have a 2005 SL600 and my dealer (within the past six months) installed a hidden sirius antenna under the hood near the washer opening and it was no big deal. Don't see why the current antenna couldn't be changed out as well. I will say that I am in Atlanta, and one dealer professed to know nothing about putting in a hidden antenna and the other one said "sure, no problem" so you might want to check with another dealer in town if you have that option.