The IO360 suits my needs just fine. I started out looking for a M20E or M20F and ended up with a M20J. I spent more than I intended and got a really nice plane for the money with Garmin 530 and HSI both coupled to an autopilot. Any comparably equipped Bonanza would be way more than I want spend as well as less economical to operate, unless it's an IO-470 on mogas. When I buy a Bo it'll be either a B33 as those are the most economical, or an S35, as those are the fastest for the money. If I was you and wanted to beat the airlines reliably flying out of Chicago, I would probably want a B-58P with TKS and a deice prop... or a BE-200. Hell yeah I'm biased,
I would never consider a Cessna 400 or a SR-22, those planes are for sissies.
You must have misquoted something because your information on the IO-360 is completely inaccurate for a M20J and I don't believe any Bonanzas have a 4 cyl. Lycoming IO-360 up front.
In level flight at 3000ft with everything forward, I easily see 165kt/190mph at 16.xgph. Pull the prop back to 2400 and lean to 1425f. EGT and I get about 11.8gph at basically the same speed. I usually adjust my power to about 9.5gph and I can get 150kt. I fly my plane this way because while it is 15kt slower, it is also $34/hr cheaper in fuel flow, which is a consequential amount of money to me. Climbing out at gross I get about 500fpm at 110-130kt. Fuel to the tabs (50 gal.) and 295lbs in the cabin I get about 750-1000 fpm initial climb at the same cruise climb speeds. I never climb at Vy. In descents I maintain cruise power accelerate to 190kt descending 300fpm and I enter downwind at 130kt., drop the gear, decelerate to 100kt on downwind abeam the numbers. 80kt. base, 71kt on final.
Sorry, but I really think you're talking out of your ass because most of the Bonanzas with big sixes have IO-520s or IO-550s which aren't even made by the same company as IO-540s and any way you cut it, they're going to burn a lot more gas than a 4 cylinder and cost more for MX which is precisely what I am not looking for.
Good luck with your flight training, you will need it. Remember to read the POH and set the correct tank on takeoff in your Bo' or you will dump all your fuel overboard.
That would never happen in a Mooney.