I think it more depends on where you are going to be racing. If you are racing club and there are others with Leopards I would stick with a Leopard. They are readily available and have many years of stable running under them. The X30 is a good motor too but currently it seems to be going through some changes and not worth the expense of chasing the changes in the next year or so. If you are going to race with Skusa I guess they have made the decision for you and to be competitive you will need to but both engines for next year. If you show up to a track and the Leopard is faster you better have one, vise versa of course. I understand what they are trying to do but in the end its just going to cost racers a ton of money to get the same performance as they do now. If you are starting out I would definitely go with a leopard as a one or two year old motor is about 1/2 the price of a x3o. That’s a lot of racing you can do. Just two cents for what its worth.