The fact you (or Kirk) didn't realize this was a cheetah topend after owning it says a lot to me. How in the fuck did you not catch that??? The size of transfers on the cylinder visually as well as the fact it takes cr250 reed cages not cr500. Or the rear stud locations.
Or the fact it didn't have a mattoon clutch setup??? You never once took the clutch cover off? It says NMotion right on it. Or notice the clutch cover didn't extend an abnormal amount to hold the 11plate? (usually these have the mattoon billet clutch covers as well) I'm surprised it had straight cuts in it when he pulled the cover off, LOL...
I also think that PPS should have seen a few of these tell tale signs when looking at the bike.... but as soon as he got the bike back to the shop and caught them.
Another thing is that you had been having ignition issues with this motor. The flywheel/stator problem... then found it was coil's. The stretched threads are a perfect indicator you fucked that up when pulling the flywheel (didn't you have to replace the flywheel as well?).
The cross threaded shaft is another newb mistake. You just didn't know what you were doing and kept gunning it on after it was screwed up.
Kirk sold you something not as advertised? YES. but you bought it and never even realized it. Now you're selling something you have no idea how to maintain and is WAY over your head and think it's Kirk's fault? NO
This would be easy to deal with by trading back, then dealing with Kirk about getting something not as adverstised. A cheetah topend is not worth near what a DM topend would be as far as resale value goes, I don't care what anyone says.
As I see it, you owe PPS a billet shaft, an 11plate clutch setup, a DM triple topend, and pay to fix the crank end. He can give you back the broken shaft, nine plate and cheetah topend.... OR just trade him back!