MT has a new STC to replace the PT6A-42 on a Piper M500/Meridian with a -135A (and one of their props, of course). Unusual for an engine swap to a less powerful engine, in this case from a "medium" to a "small" PT6. They claim similar speeds, longer range, quieter, and lower operating costs comparable to the piston M350/Mirage. Does anyone have any more information about this, besides what's in the press release?
https://www.mt-propeller.com/en/entw/pro_meridian.htm

Ashame they can’t ditch the always on ice door. Would gain even more speed and range I bet.

That STC has been around for a while. I am have not heard of any sales. No doubt a new engine is expensive.

Install cost aside that is exactly what I always hoped Piper would make. Now that Piper has M600/M700 on the high end they should open up the lower price with this configuration. It’s basically a JetProp engine on the newer and better Meridian wing. Depending on temperature up to a certain altitude approximately FL200 both engines have the same power because they are limited in the airframe.

Above a certain altitude that day the 35 series engine will temp out and be a bit slower. In exchange the 35 offers much lower fuel flow especially at lower altitudes. The difference can be significant. The range numbers shown are far beyond anything the Meridian donor could have done.

Jetprop gets a bit of that high altitude performance back with the intake scoop. Interesting that was not pursued in this install. I am sure that would have been a lot more work and expense.

This install would have been attractive to me when I owned a Meridian.

I reached out last year. PM me your email and I'll forward info. Or you can email Martin Albrecht, martin.albrecht@mt-propeller.com.. He sent me their info, but essentially $900,000 plus 500 hours of labor to do. They had 2 engines on order for April 2025 and 4 for 2026, represented that they had sold 1 for 2025.

They would prorate a first run engine, ($45/hr up to 1000 hours). I have a hard time visualizing the benefit of 1.4 mil swap or even a $900,000 engine swap. I would be much better using that kind of cash to upgrade to a 600 that solves any problem that could be mitigated with a lighter more fuel efficient -135A. You save 55-66lbs.