Where can I purchase smaller standoffs for the DA 50?

Also, what is the most powerful muffler for the DA, If it is more noisy that is an added bonus?

The engine came with those four socket head screws surrounding the center shaft but the center shaft did not come with a screw or a bolt and the threads are on the inside of the drive shaft. Where can I get a contraption that will fix that problem?

Also, I am going to purchase a Carbon Fiber spinner for the engine but in the manual it says that there should be nothing between the prop and the drive washer. Will a good back plate work without hurting anything, how do I get around that problem?

I need advice!!!