231 is your best bang for buck. I owned a very nice example with a merlyn controller and the more desirable airflow systems intercooler. I never had any cooling issues and had no trouble keeping the CHT's under 380 all the time on the LB engine. Typical temps were 330-360. Burned 9.5-13 gph in cruise depending on how you like to run it, 18 in cruise climb and 24.9 on take off. Cruised 160TAS with ease at Lower power settings and 170TAS up in the high teens. We saw 200 plus over the ground on many trips in mid teens. All in it cost me 170 bucks per hour over the span I owned it, less than most sky hawks rent for where I live. This is all in after sold, includes maintenance, upgrades, fuel, oil, hangar, etc.. It was and still is a great airplane for the money. You have any questions on costs, maintenance, operations on the 231, etc shoot me a message, happy to share my experience with the K model. I still have every receipt for every penny I spent on that bird and have some good cost to own spreadsheets if your curious.