First off you know the engine we are talking about is an onroad engine? as far as parts go They would be very hard to find i would think no were would have a piston and liner combo instock except maby the factory maby. rods and bearings are as per normal sirio 21 just the racing versions of rear bearing and conrod. The engine will not like that fuel mix the 21 wcr is a stright out race engine and all sirio engine hate lots of oil. Also there is no need to run 30% nitro in this engine its plenty fast use 25% you will get better life and the paformance will be impressive to say the least. Exspect around 5 min run time from this engine same as most high end race 21 on-road engines. But the bigiest thing at the moment for you is fuel you need a better fuel a race brew and parts will probaly be very hard to get apart from bearings and conrods. Regards Jeremy.