stock pipe, I also re-did the canopy and got rid of the hinge and made a locking canopy with pins to the front. I forgot to lock the canopy on my 6th flight and luckily it opened on take off and the damage was relatively minor.
I also put in a new large tank above the turbine instead of in front of the ducts for a more balanced CG in flight.
I also moved the CG back 1.5"