As others have pointed out, between a Cherokee 235/Dakota and a Comanche 260
you are really talking about two different classes of performance. The
primary difference is that the RG of the Comanche gives a big boost in
cruise speed and a smaller boost in climb rate from engines of comparable
power.

Looking specifically at climb and high altitude performance, there is a
difference between the Dakota and older Cherokee 235/Pathfinder models with
the "Hershey Bar" wing. For example, compare "book" service ceilings:
17,500 ft for the Dakota and only 14,500 for the 235C. The longer wing
provides higher L/D, which is what you want if you need to fly high.

If you are going to consider RG airplanes in the same performance class as a
Dakota or a Cessna 182 then what you are looking at is an Arrow III or IV, a
Cessna Cardinal RG, or a 200 HP Mooney. The Mooney is quite a bit faster
but all three have service ceilings similar to that of the Dakota. The
Arrow III/IV and Dakota provide interesting comparisons because their
airframes are of virtually identical dimensions. They boast virtually the
same cruise speed and the Arrow service ceiling is just a little lower at
16,200 ft. The useful load of the Dakota is certainly larger, but a good
portion of the difference is eaten up in higher fuel requirements if you are
flying any distance.

If I were based at Colorado Springs I'd certainly consider a turbocharged
airplane, particularly if much of my flying took me west over the Front
Range.

-Elliott Drucker