Not the answer your looking for but I have seen the Mercury 3.0 four cylinder 150HP on a 19-6 (same as 200) and a 222. Performs very well and is light for a four stroke. One of them had well over 2000 hours on it.
I personally would hang an Etec on it. Not sure if your looking at used or new... They have a killer warranty offer going right now on new ones. Used ones will connect right up to your existing engine harness and steering.