Welcome. As most here know I'm full of opinions..maybe too much so..lol There are pros and cons with everything in life but in cases like this, if price or cost isn't a factor, get the one that does what you want best. CFMs have a wide range of expected miles from as low as 1000 to many have more then 10,000 miles. Parts may be cheaper for the CFM but may go through more where the opposite may be the case with the C/A. The cargo capacity is probably higher on the C/A then the Z8...ect.
Now for an opinion on extra seating: I know people do it..just like riding 2-up on a 1-up ATV.. but it is my opinion that adding seating to place people outside the safety of the roll cage is..well..just not the right thing to do. As an operator/owner, the safety and well being of our passengers must always be the #1 consideration. JMO..but I sure don't want to be the one that caused my grandchild or friend's death or left paralyzed for life. I say if you need a 4+ seater..then that's what one needs to be looking at.