Sounds like the problem is how its being put back on the shee.Ricky Stator is known mainly for two things, timing plates, and STATORS ,they stand behind their products ,if the first one was broken, their not going to send you another broken one.
Green Machine is in Miami the number is (305)828-0917 they specialize in Banshee's.Also,Tony Dukas is in Pompano,Florida ,thats actually closer to Fort Lauderdale, which is closer to Miami then Palm Beach.
80 psi,your boys bike must run like shit nah ,cant be ,you must be checking it wrong.But, if you check properly and get those same numbers ,both of your buddys motors need to be rebuilt.
Your not even close to needing an extended swingarm.If anything ,you should probably cut two inches off the stock swingarm ,with those mods youll have alot more fun.
You need to have your carbs taken apart and cleaned properly.And regarding the radiator fluid Banshee's tend to leak fluid from the reserve when ran hard ,some people move the reserve or eliminate it all together.Do a search most questions are already answered.