I don't know Stingers, and there are no pics here, but I may still be able to help. Take a long hard look at the fit and finish. If you have the tools and know-how to put it back together, take it apart and check it out. You may see some things that will give you trouble later, or parts you may want to change out for something better.
Basically, you want to get an idea if it will be worth the trouble to you. I have heard that these little 2-stroke engines can differ greatly in quality, often even ones from the same manufacturer. About all you can do is determine if yours is made well enough to run for a good while. Then, it's up to you to assemble and mount it correctly, check all nuts, bolts, fittings, carburettor set-up, proper break-in procedures, maybe a better spark plug, etc.
The better it's adjusted and treated, the better it'll run.