An 8x6 and in the plane would not start cold has to be warm , vibration not bad , a buzz comes down the lines a little ,,,, more power than the stock motor ,,,,,, thank goodness considering all the mods , shaft is quite loose, rod holding up OK , its only 2011 free machining aluminium , no bushes , I had at least 8 flights, more like 12 , at the highest power I could get no sign of burndown even when set real lean , Im not pushing the compression , just till it stops burping, Ive got 20% castor in