Clarification: The add-on kits are ONLY for radios that are indicated to already be Sirius/XM ready. If the front of the radio doesn't say it's Sirius/XM ready, there is no jack on the back of the radio to plug the kit into. You'll still need to install an antenna, which is the real problem. If you lay it on the dash, you'll have great reception when you're driving south, no reception when driving north and good reception driving east or west (the satellites are all over the equator). Even if you get the separate unit, you'll still have to figure out how to run the antenna.
2015 Legacy SR340 360RB
2014 Jeep Wrangler Unlimited Toad
Gigi, Poppy and Sadie Lady...On the road, but not full time!