This question pops up from time to time, of course more power is desirable so I personally would say 199hp is the best but its got to be taken into context. Out of all your future journeys how many will you take fully loaded as opposed to daily drives or weekend trips.
When I say fully loaded I mean as we do three weeks traversing mainland Europe loaded to the gunwale's, including a tow bar mounted bike rack C/W two bikes and anything else I can get on there safely within GVW.
We have done several drives of 4/5 hours across Europe at 130kph returning healthy Mpg.
No regrets buying a 150hp. Its our Third Cali the first had the 140hp
As Meoncoast says try both before you commit, if your unsure. I could have bought a 199hp 4 Motion, but do I need 4x4 No, do I intend to pull two horses in a box or a 2/3 axel car transporter to track days anymore No, so we made the choice based on our needs.
What ever you decide it will be a Cali enjoy.