If they are the JX14001 & JX14002 L and C manifolds, I would assume they are the same as the L header from the 2050 OS pipeset and the C shaped from the 2060 OS pipeset. They are very durable IMO if they are the same. Use L shape for more lowend torque and C shaped for smoother power delivery. Mugen only has the EFRA 2042 pipe listed (OS 2060 pipe)