We can't answer all of your questions, because some of them are outside of the Customer Support area...

1) Sorry, no videos
2) See the above post
3) Exhaust rings:

OSMG2725 47069000 EXH RING OUT FR5 $239.99
OSMG2726 47069010 EXH RING IN FR5 $239.99

"OUT" mounts in front of the engine, "IN" mounts behind the engine. The collector ring can be ordered through the same retailer where you order the engine.

4), 5) We believe the engine runs very well and is very user-friendly if properly broken-in and run.

6) We'd suggest at least a 24 oz fuel tank. This engine has a 50cc displacement, so it will be a bit thirsty. We don't have a specific fuel consumption, but that size tank at full throttle will go about 12-15 minutes.