I want to order the Garmin 4212 network bundle with the sonar and xm. I know I need a transducer, do I need anything else for the install?  Nothing else needed aside from the ducer

What transducer do you recommend? I would either install a standard transom mount, or get the tilted element Airmar. I have a single outboard engine. Do they make a tilted element Airmar B60 for the Garmin? Is the transducer elements the same, just in a different mounting package?   On a single outboard boat the transom mount P66 is fine, although if possible I'd so go with the B60.  These are the same guts in different packaging.

Does the 4212 need a separate antenna for the XM radio, or does it share the GPS?  - The 4212 needs a separate antenna, its included with the GDL30a weather module.

Do you have the screen protectors for a Garmin? - No, but thee is a company called "Purplemoo.com" that does.

Are there any rebates, or any coming up that you know of?  - No, nothing coming up.