I used my .12 Sirio ACC for 6 months racing and I was doing well with it, (before I hit a fence and snapped the crank). When I open engine you could see oil movement between conrod and crank (Piston/sleeve pinch is still very very good). This wear surprised me. My .21 Hyper 8 port that has been used a lot more (around 3 or 4 times) was in much better condition. So I swapped engine brands, the current .12 engine I have now is coming up to 6 months racing and I do not see any movement in conrod bushing (there would be some but not visible, the sirio movement was!!)

But there always is a positive, and that is the engine I am using now smokes the Sirio I had I'm going faster ! hehehe

BTW - Conrods for the engine I am using are $15..