Yep, I'll take one.

Do you still have to remove the original chips for a Mk2a? I assume yes but you only mention that it's necessary for the Mk2 in your post. If not, the original chips are redundant, right?

And there is enough room underneath the PCB right? I don't remember huge amounts of space between the board and metal case but we are talking only one surface mount chip thickness plus PCB (~3mm?)