Had a long convo with Morris about this upgrade, which I'd never heard of before. Basically what they did was computer design and improved the flow inside the engine on the Super 5's to add a lot of power to them, and it costs about $60K/side to do this at overhaul. However, that gives you top speed of 282kts, which is a lot better than the 265-270kts you see for regular 5's. That's pretty close to -10 performance, for maybe a third of the cost, as the -10 conversion runs a good $120K/side for mounts, engineering etc, plus the STC cost. Probably close to $200K side when all is said and done. That's on top of what the more expensive engine costs. Only drawback is you have to do two hots, rather than one on the -10's, but it'll still be a cheaper option.
Why don't more people do them? And did you even know this was an option?