"I don't understand why, if the 152/172 airframe is so good, they are not worthy of an engine/avionics upgrade. Shirley a complete stripdown, repaint, new carpets & busted trim replaced shouldn't cost more than a new unproven a/c"
Someone has
Cessna Rotax
However (in my opinion) I don't think it reduces the running costs enough to be successful.
If they swapped out the wobbly prop for a fixed one. Improved the fuel efficiently by installing the fuel injected version and approved it to run on Mogas with 10% ethanol then it might be in with a chance.
The conversion costs a hell of a lot mind but I do wish them well.