My first motor was a Mc-10 I got for X-Mas when I was 13. When I was told it was obsolete and non competitive it broke My heart but it was still fast and fun and I wish I still had it. It’s worth a bit more then the $35.00 My Dad paid for it. So I saved My paper route money for 3 or 4 months and got a Mc-91A. As for a new Karter. If Your Enduro racing either a B&S Animal or any good Piston Valve motor is easy to get Your feet wet with then decide for yourself what Your goals and aspirations are. This is all My opinion and You know what’s said about them. Happy Karting.