Keep your engine clean by making sure you change the oil and filter on schedule. You do not need flush service or the pour in flush treatment. Unless you want to f-up your engine and decrease its life. If there is sludge(doubtful) you don't want it to break off clog up the turbo oil lines, oil pump and engine passages.
Seafoam does not deteriorate the seals and cause the turbo to leak. It works with the oil and does not have to be drained when you use it. But its not a flush, its a motor treatment.