If using vaistech on an 05-09 RX you can add both ipod & xm or sirius. The ipod will work off of the disc button & the sat will work off of the AM button. The ipod install in that car literally takes 10 minutes & the xm 30 minutes. The radio is very easy to remove and there is no splicing or wire cuttin involved.
On the newer cars that have the available port installed lexus ipod you cannot add sat because the port installed ipod uses the sat function. It however can be easily removed to install both vais units.