I own a 414A with R stol. I landed at Everglades City the other day, 2400’, I was heavy on fuel but light in the cabin, I believe I could have turned off midfield with very heavy breaking, but let it roll to the end. You can get parts for the system but I can’t rember the company at the moment.
RAWL

Have you tried to get Parts lately? It’s my understanding Sierra industries sold all the STC’s.

I believe a couple years ago, and I believe you are correct about Serra industries.
RAWL

Sierra Industries is no longer in business. BK? The RSTOL STC and the very few parts that remained have gone missing:
RSTOL planes are now orphaned.

It looks like Spring Aviation LTD. may be producing parts now. Not sure I haven’t checked.
RAWL

That would be good news. Unfortunately the demand for New RSTOL at their new prices is close to zero. Hopefully they will make a few parts on demand.

I know what you mean about the prices. I understand the price was 75,000 for the twin cessnas at that time, I have no idea what it would be now.
RAWL

Thanks for the complement Don! Just one small correction, my field is 2,300 instead of 3,000'.
If you found a good airframe, and best I can tell there are less than 10 flying today, it would cost you around $500,000 to replicate my plane. Unfortunately mine is not FIKI, but I know of at least two that are. I know of one very good candidate that could be the queen of the fleet.
As for LOP, we installed GAMI's and made sure the ignition system was tip top, and the engines are very smooth at 30gph/ 33"mp, and 2,300rpm. I need new plugs, and we are doing a top overhaul right now, so that should make mine run very well.
You are right about DOC cost, but the best benefit is range. With 200 gallons of fuel on board, I have over 1,000 miles of range with 600lbs of payload. I can also go 800 miles with 800lbs of payload. That is almost a 300 mile range extension vs. running ROP.

As for parts....
It's really not a big deal. Don't forget, human hands made these parts, so human hands can make new ones. With the magic of 5 axis CNC machines, 3D printing, and laser scanning, there is nothing on this system that cannot be duplicated. And I can almost guarantee it will be cheaper than the factory parts, if you happen to find them.
The freedom to produce parts yourself makes this a relative painless process.
In 4 years I have only needed to rebuild my flap gearbox, and that cost less than $400.00.
A new box from Sierra was going to be $6,000.00 with a 3 month lead time.
I have sources for all of this if needed by anyone.

I have had my 421B STOL for 21 years. Only thing ever broke was a bicycle chain flap drive. About 25 bucks. I operate out of a 3100 field and can take off half way easily. Land by the mid turn off heavier brakes, my hangar is 3/4 ways down and alway make my turnoff light breaking.

Now I tend to operate it closer to regular 421 speeds until I get to Baja then it’s a big 182.

On the STOL issue, I'll mention I know someone who bases his non-STOL 340 at a 2500' field. He says you just have to be careful about weight and DA, and he flies a long stabilized final. For me, it's really take-off that is uncomfortable on short fields, not landing.

I wonder if Jerry is watching this Thread

With micro VG's I don't think that would be an issue. I rotate at 75 knots and fly off at 80knots from my field, which is about 10 knots over Vmc. If I lose one at rotation I will have to do everything right or its going to be a bad day, but that is a very small window of less than 5 seconds. I limit my operations here at the house to 500# below gross and that gives me pretty good performance. It's not for everyone, and I try to mitigate the risk as much as possible with good maintenance and training.

I had a 1978 Ram VII 340 with VG’s. Landing in 1500 feet was not a problem.

I could takeoff in 2000 feet with no problem and on a standard day if there were no significant obstacles.

I loved that 340 and Wish I had it back.

I owned a R-STOL C340 with Ram VII engines. Flightaware has its last flight in 2012. I sold it in 2008 and it was in excellent condition. I hope it isn't sitting rotting somewhere in FL. Tail # was N340CC.