From the info given it would seem that the SA220 is not really a power house. I mean the SA180 is already a real gas guzzler and now we see that the performance is only a little better than something like an OS160. From my personal experience running a TT120 2C, the engine does not really consume that much fuel, there is a possibility that the SA220 has the same consumption as th SA220. The SA220 may be a 4C engine but then if its like the SA180 means fuel consumption is heavy. Only benefit is that the SA220 will be able to throw a 20" prop.
How much is the YS160 compared with the SA220 ... the YS160 can handle a 18x8 with ease.