A friend of mine made a 4-port Meth set up for his car. I think he used a Boomba Spacer to make it. It works pretty well, made most of the kit himself.
I researched doing a four port aux fuel using the Boomba aux fuel spacer, it's pretty cost effective at around $850.00 for all of the components including the spacer. Its got the ports already for meth injection which makes it even easier. Only downside is that only one valve per cylinder gets washed with fuel. But for $400.00 in savings, using the CRC intake valve cleaner at the port at the throttle body every oil change is a good alternative.