Agree with Tom about the stern lift and 4 blades with the Suzuki 140. I have a 2007 140 on my Caracal Cat, with a SS 4 blade. See if a dealer has a loan program where you can try a prop for a day and if it works;Good, if not then try a different prop.
The Newer 140's put out about 20 more in mid range and turn slightly higher at the rev limiter (6200 to 6300). If you really want more power out of the 140, let me know. Mark Grove (who recently sold Wefings boat dealership) has a way to get 170+ hp and better speed and economy in mid range on these newer motors.
I run SS props, unless planing to run into debris or grounding. The SS is thinner slightly more efficient because less flex than the Aluminum.