Isn't the core only used for OSD and voltage regulation? I have not done a lot of looking into the TBS, but I know I want one. There is a guy on here that just sold one. Would have loved to have gotten it, but money just wasn't with me at the time. The TBS and QAV are the same design and about the same price, so from what I can see, it's dealers choice. There are differences though as there are with any aircraft variant.