If you do opt for a PT pipe pretty sure you could score a used one if you keep your eyes open.Also PT made a midrange and a hi rev pipe for the 250,s...Pretty sure only the midrange pipe is available from Duncan.
I,ve also heard the Shearer is supposed to be #1 but have never run one.Someone is planning a dyno session,results should be interesting.
Plenty of decent pipes out there,how much difference there is I don,t know.What year 250 do you have?