I just got a pre owned nitro jato a few weeks back and the engine attached was a TRX 3.3 and the previous owner had broken the piston rod, he made sure I was aware and gave me a Discontinued OS Max 18 cvr nitro engine that has never been ran with it. How do I piece this thing together and should I just buy a new piston for the 3.3 engine already attached or should I go with the OS engine as I've heard its a uncommon and expensive high performance engine? Both engines are missing the pull starter and the OS replacement starter is $50 alone so I just need advice on whats more worth my time and effort and money when it comes to this jato. Also most of the chassis and body are upgraded to alum parts. Ill attach photos to the post and thanks for any help.