Awat, there are few who have ran the OS 160 more than my friend and I with as many different combinations as we have. We tried nearly all major props and fuel combos and have found that the OS 160 performs best on 5% fuel, Zinger pro 18 X 6 ( the Mejicklek 18 X 6 is good too) and a Macs header and mouse can pipe. Now if you go pitts, I would go with SLimline over Bisson. Jerry Smith has a manual you can buy for $5 and it tells how to build a mousse can muffler for various engines. We fly at 500 msl. Hope this helps. Jeff Williams