The piping was for a stock k20 RSX with PRB manifold. With my K24 and RBC none of the piping fit correctly. So I had to cut, extend, reangle, etc and basically make a new setup. So I bought a 2' coupler and a universal piping kit.

As far as the solenoid no I don't know the benefits of a 4 port. Actually truthfully I didn't know there was a 4 port. I'm only familiar with the 3 port.