Repower 21

[capnkid]

Here is what I got want some opinions.
21' seacraft 2000 (i think or 2001). Right now 200 optimax on the back that we are going to re power.
I really really do NOT want to go with another merc. That said I think i am down to the following
200 etech
175 zuke
Want to go 4 stroke but afraid the 175 zuke may be underpowered?
Any 4 stroke yammy is going to be to heavy same with honda. 150 fourstroke is to underpowered.
Max weight on transom is 550 (i believe?)
Was curious if anyone had any experiences or opinions on this boat/or engine.
I am not trying to start an engine bashing thread.