Terrova with US2--different transducer

I was fixing to pull the trigger on a terrova with Ipilot, but have a couple questions. They only come with US2 standard, but I'm running an 858 HD DI at the bow, so I will have to attach the HB transducer. Is there plenty of room for it (I use a transducer shield and saver mount)? Second, does the us2 only ping when a unit is hooked up to it? In other words, will it cause any interference/bad readings with the external transducer? Thanks guys.
I had a terrova on my previous boat, didnt order new boat with one cause I thought it wasn't that much better, now here I am, about to order one to replace the cable steer...that's what I get for thinking!

You don't have to hook it up, it will be out of the way and no it won't ping unless something hooked up and turned on.

Will the US2 not work with DI at all or just your model. I knew it would not work with SI, but I was planning to put a DI unit up front this year. Wil any DIs work with the US2??
SeaRay

No, only 2d sonar with us2

OK so no Di with the US2, but you can use a TM mounted transducer for Di but not SI, correct??

You can use a tm mounted transducer for SI, but any rotation of trolling motor will distort your side images. But there are a lot of guys on here that mount SI to tm with great success. Maybe some of them will chime in for you, or do a search to find some threads on it.

Yes SeaRay you can mount your DI transducer to your troller and it will work fine. Best picture will be pointed ahead and moving slowly but they will still work if your rotating head.

US3,just hope it well retrofet to terrova

If it helps, here's how my 1197 transducer is mounted. Some (all?) of the HB cables will fit in the channel in the Terrova's shaft. Unless something has changed, Lowrance cables won't.

http://i267.photobucket.com/albums/i...psa1659a17.jpg