Could use some input. Sold my previous car for salvage when the engine blew. I had a Lifetime Sirius subscription for the car audio system at the time. I have now purchased a motorhome which has a sirius radio. Should I transfer my Lifetime Sub to the factory radio or to a Sirius Portable and use the Aux input? My concern is which radio is going to holdup best as the Lifetime Sub can only be transferred a limited number of times. If the portable, which model would you suggest?