Using the Bonanza conversions and the Piper Malibu vs the Meridian references the answer is no. That said the most fuel that can be put on a bonanza with tip tanks is 114 gallons and they still have about 700-800 miles range. Take a Mooney carrying 130 gallons and being a smaller, lighter more aerodynamic airplane it likely could add 200 miles to the range while going faster. A B36TC is good for 250 KTAS with the PT6 rocket conversion.
Correct me if I am wrong. I have been told that it takes 8 times the power to go twice as fast. Using that logic and taking an Acclaim at 25,000 running 75% power (262HP) and going about 240KTAS then just about doubling the power to 500HP PT6-42 that has so much reserve thermodynamic power it still makes 500HP at 25,000 feet would add about 20-25% in speed or around 290 KTAS. problem is you would be going about 190 KIAS and you loose the yellow arc when you put a turboprop on it. What is the top of the green on an Acclaim? On a 201 it tops out at 175. would doing 260 at 25,000 feet be worth it?
I don't think it is worth it with a PT6. The one I would live to see is the Allison engine. It is very light and that would do two things, eliminate the need for any type of weight in the tail it may even require moving the batteries up front further reducing weight by eliminating the large wires running to the tail and offset some of the weight gained carrying m heavier fuel.
The performance gain would be awesome at lower altitudes but not life changing. At quick glance it a 420/450 HP engine. Not really, at that setting you are in the 5 min torque range and that assumes the density altitude allows you to do that without over temping the engine. In reality it is a 380 HP engine up in to the teens. At 25,000 a stock piston powered Acclaim might go faster. at that altitude it has lost so much power the piston engine is making more power burning less gas. That is based on the Alison powered Cessna 210 vs the Vitatoe conversion that has a 550 continental very similar to the 310HP Acclaim engine.
So why would I want a Allison powered Mooney? I want an Allison powered because I want to go very fast with out wearing a nose hose/mask. these engines are at home at 8-17,000 feet depending on temperature. i got a ride in a Bonanza with the Allison engine and the experience can't be expressed with words on a computer screen. It was smooth, quiet, climbs better than a baron while burning less (28 GPH). At 9,000 feet in the summer (I didn't look at the density altitude? it was burning 20-21 GPH doing 180. I bet it would do 200-210 in a Mooney.
$1.3-1.5 million new?