not saying the 4C engine is not powerful.... Just fine in an LA2 or T2A-Mk-4 - or one of the mutant daddy rabbits in SPA

Just that 4C does not "belong" in a Tipo
I flew 3 Tipo aircraft competitively ... one original 720 and two 750 size
None YS powered.
Today, there are superior 2c powerplants to anything I flew back in the 80s.

I'd imagine a YS63 might fit, probably adequate power. Maybe a YS110.

Quiet impressive .... 157mph lancair --- some serious muscle in the saito 100.