Looks like I'm a bit late on a reply, but I will still provide a bit of info that I've picked up recently. I live about 45 minutes from Stedman's shop. The SRP intercooled plenum is now provided by The Motorhead (Dennis Clanton, LSR) and Jay Stedman(Drag) who is doing the majority of fabrication these days. Dennis and Jay are now brainstorming together, so I guess you could say that you have the Ghetto and the SRP combined. You can see the improvements in the quality of Jay's fabrication and welds due the increase in experience since he has more time to dedicate to fab and customer needs. Check out the various photos that Stedman Motorsports has posted as well as on his other related Facebook pages. Motorhead and Jay have both, in the past, had some parts fabricated by Richard (RCC) for their own brands of turbo kits and, as I understand, have a few shared past concepts. Recently several people have redone their turbo setups through Stedman.
From what I understand, Dennis' newest L/A design should flow quite a bit more in terms of airflow and water flow than previous designs. I will not state the percentages that he told me. BTW, I believe that the plenum that is on ebay is of the latest core design, if it is the same one that they had sitting on the shelf when I stopped by last, but you would need to contact them to be sure.
It appears that they also can provide a nice L/A intercooled setup for the ZX14 intake design.
I do not have any personal experience with intercooled plenums from any fabricator yet, so again, this is just MY understanding of info that I've obtained from speaking with both Jay and Dennis and seeing customers bikes at the shop one day. SRP also intends to bring billet plenums to the table soon, after design and I guess a bit of R&D of course.
I am not affiliated with Stedman Motorsports, SRP turbos, Ghetto turbos or whatever. Just a guy "local" to Stedman. I will only add a note that Jay's previous assistant(s) seemed to be a bit inconsistent or even just being understaffed, which led to Jay being overworked and overbooked, so hopefully now and in the future, there won't be any of those bad experiences, but every shop has some from time to time I guess. Later guys. (one more time....don't bash me please, lol. Just trying to speak for a guy who is quite nice and will share his knowledge. both of them actually. I don't know if they visit forums anymore)