Based on what I heard about the YS 110FZ.
the engine turn about 500 rpm more with same prop and fuel used on YS 91FZ.

Keith,
How are you doing?

You don't have to worry about the price on YS110.
I am sure that when it becomes available here in the US, the Famed Central Hobbies will have the lowest price available to all of us.
If the actual cost to get the engine from Japan will be around $450 because of tax and other fees.

I still don't have any answer from the hobby shop in Japan for the availability of the engine. Last time I heard was last November, but it became end of this month or early next month for Japanese store.

So, I am going to try my TT120 rear exhaust before getting the YS110.