If your plane is .60 size the best you could do is to place .91 engine, it is the
same weight and consumes a bit more fuel but you have lot more power when
you needed it. And the Power is newer enough; the worse feeling is when
you feel you are underpowered, isn't it, not only in Aviation
The guys on RCU seems to agreed that there are many very good ones,
some are copies of the OS.91 some are not, but all seems to have pretty
descent Power-to-Weight ratio better than any .60 size.