Satellite radio tuners

You didn't give any details about your two channel system but if it will take an airplay stream that is your best bet.  Sirius bandwidth is < than what airplay will process so you won't lose quality from your iPad. 

Kenwood made a standalone Sirius/XM only tuner. I have one in my system. I don’t use it very much anymore, but it sounds pretty decent.

ST-7000S is the model.

I had a Polk dedicated XM streamer.  Came with it's own antenna.  It's gone now, XM for the car only with all the better resolution options inside.  But I do still discover new music while driving on XM.  I snap a quick pic and then look for it later on Qobuz.

XM sounds like poop. Streaming is the "best" format for satellite radio. There are dedicated tuners, but really, just stream through a device. 

XM are also thieves! Try to cancel your subscription. You will be on the phone for 2+ hours. After that they SPAM you with emails and snail mail. Such a shady company. Canceled over a year ago, then they pop a $350 charge on my CC, but my service does not work. They refuse to give me a refund, and actually prorated it, even though my service was not active. It took over 2 hours to cancel it again. 

As another commenter mentioned , Kenwood back in 2004 when Sirius XM begin made a good tuner.It is a DT-7000S. 3 times the size of the stuff they're making today guess because few have it hooked to a home system but I do. It is 2 channel with a nice display and it looks o.k. too. If you have a good system it sounds pretty good with an acceptable soundstage. I'd say it's comparable in sound quality to your average FM stereo radios but not close to the McIntosh MR-71 I have. You can find them on Ebay for $125-150. You may not get an operational guarantee from the seller because most don't have the Sirius subscription so the unit is untested. The one I bought couple of years ago works fine. Even found a remote for it from another seller. Likely a universal one would work but not sure. Having a remote for me is a must. I found an antenna on Amazon that operates it well from Tram with a nice long cord so you can place it near a window. Sirius raised their band into the 300's recently but this old timer only goes to about station 185 though.