I have a Saito 90TS. It is much more powerful than the older two carb .90 engine. It turned a APC 14X6 at 9600 rpm peaked on Byron 15% nitro/20% oil. I had this engine in my Great Planes Spacewalker. It was a perfect match scale for power. Aerobatics would require a dive for speed prior to doing a cuban eight or loop. I had to use a Kline regulator to stop the left cylinder from flaming out during aerobatics.

I also have a O.S. 160 twin with the new carb. It is as strong as a Saito 150 but weighs about 9-11 oz more. If you like twins and have a plane that could use nose weight and less vibration go for it. The these twins are very, very smooth at all rpm levels.