I've had my 2011 RTL for about 8 weeks now and just found out i got a 90 day trial of XM radio starting when I took delivery. I noticed the sound of FM & XM channels get thin and don't really get any louder once the volume goes over 30. CD & AUX modes sound fine, although I dont need to crank them up as much. I saw someone mention that reception is poor on the RL, is this a possible explanation?