Something to consider is that the B.T, sidewinder, and the MR intake have the
oil fill provision in the manifold. The CJ maniflold is an iron version of the PI manifold. The BT is a very slightly tweaked version of the MR. For visual reasons I prefer the BT. My car has a RPM. Also the the RPM manifold does not have PCV valve hole machined in (the boss is their) which is used for the
oil return line from the puke tank. My $0.02