I have a Saito .80 on a PTS, and it's not overpowered at all. In fact, with a Master Airscrew 13x6 "Scimitar Profile" prop, it's a bit slower than with the normal PTS 2-stroke engine, but the vertical performance is great. The only caveat is that the .80, being an older engine, is large and doesn't fit the cowl very well. A new .72 or .82 would be a lot easier to fit.

Unfortunately, after about 15 flights I discovered that I hadn't fuel-proofed the firewall as well as I'd thought. Fuel had gotten in around the edge and the firewall was starting to turn to mush and pull away from the fuselage. So she's grounded until I can get that fixed.