From what I’ve heard (nothing on paper though) is that Roder has plans to reintroduce the STC for the 182. Hopefully it’ll be for a couple more models. I believe the original STC was limited to P and Q models.
You’ll lose some payload as the engine is heavier. If you add the Trolltune STC (for P an Q models), it’ll take 2 hours and 20 minutes flying to reach landing weight. For later models you’ll have the same limitation of course.
Fully loaded at ISA+10 I seem to always reach FL100 in around 15 mins departing from sea level. How does that compare with the Avgas version?