like tries says, for used parts, check ebay, forums, craigslist, availability will be sketchy. you can get new parts very reasonable, the tool tray is approx $5 new, pod air filter $20, used OEM airbox probably more expensive used on ebay than new?
for head gasket leak, try a washer or 2 under the head bolts, sometimes with the BBK the cylinder is slightly shorter so you don't get the head properly torqued down.
Super 9 LC is premium scooter, do you really want a 49cc scoot that goes 60mph with no brakes, and bad handling? Aprilia SR50's are cool, but I like Super 9 LC much better, mainly cause runs same or better than SR50 and since has less fancy tech you don't need like fuel injection, easier to work on, cost lots less $'s. Cheers