Maybe in an attempt to show the FTC they can play nice or maybe to garner more public support, XM and Sirius are announcing “pre-plans” to change their pricing structure in the near future. Assuming the companies are allowed to merge, they want to offer lower monthly rates, letting people pick smaller channel packages for prices much lower than either company offers now.

Some are quite low - $7 a month for 50 channels, with the option of adding more channels at a small rate. They are also looking to cater to specific groups, such as those who don't want “adult” programming:

The combined company also plans to offer a handful of new programming packages, including a "family-friendly" bundle of channels, capable of blocking "adult-themed" programming, starting at $11.99 per month and "mostly music" and "news, sports and talk" packages that cost $9.99 per month.
Not all of the new pricing schemes are a terrible good deal, as some would require the purchase of a new radio capable of picking up both Sirius and XM feeds. Not good for existing customers, but for new subscribers it might be a perfect fit.

Also, it seems with the merger, they won't be “raising” their price model to access all the channels both companies provide – with a $17 monthly bringing in about 300 channels. It isn't all about good will, but keeping their promise regarding price changes if they were allowed to merge. Given that they are the only satellite radio providers that exist, the concerns over monopoly abuse are running high.