Ok, word is it's ok to post these now. They aren't quite ready but, should be in a couple weeks. I don't want to take away from your question about the tunnel ram but, this is a better alternative IMHO
This is a intake plate replacement
Glacier Diesel is making called the
Air Boss. The top has been raised to gain .75" more flow area through the plenum. Good news for those back cylinders.
The price is low and very competitive to anything else out there. When I hear the final pricing, I'll post it or Richard will likely post in his forum here.
I should have one on my truck shortly to post some pictures of it mounted. As I said, Richard isn't ready to sell these immediately but, if you're interested I'm sure he'd like to talk to you.