I am more than happy While using the customer support. I have not received my engine however but thus far so superior. thankyouThe RB25DE cylinder head from the A31 Cefiro C33 Laurel or R32 Skyline (aka: Non VCT) is usually used. The RB25DET (from the R33 Skyline or C34 Laurel or Stagea) head can be used, however an external oil feed need to be fab