Tan - some simple comments: Cavity not being at the end of the linac straight section is desirable not only for possible future 1 GeV upgrade but lower cavity voltage requirement. If the linac delivers upon energy spread and energy COM error of 80 KeV - what is the requirement for Booster flatness - that is the question. The Buncher cavity is not intended to change linac COM but to correct spread. Therefor Buncher will not provide or receive energy from the beam. The Buncher will have a range of locations in the ARC that are acceptable - seems like it should not be difficult to find a suitable open spot. I wonder if in the MR tunnel section should be avoided due to other issues - like beam noise from switchyard, temperature stability or accessibility.