It is pretty simple.....
If you want more power, cubic inches is the way to go....
Going from 225 to 273 is a 21% increase in cubes. You are really going to feel that.....
The cost is another thing....
this asks the question: can you get 21% more from the /6 in an easy and economical manner and maintain reliability? and, are you okay with "only" 21% more, or do you see yourself wanting more than that?
by design, that 21% might be the ceiling in terms of economics vs that being the floor of the 273
(yes, i fully understand that you can build a super gnarly fire-breathing slant but that costs a whole bunch of money)