CBurnside - I was able to dyno 500. 08 hp with a Hot Juice/Ez combo last fall. I was running a PS62. The EGT's were getting up there (1400+), and I was getting a lot of defueling from the Hot Juice when turned up.
That said - It was an excellent daily driver, and I towed (with the boxes set low) with no EGT problems.
After changing some of my horsepower goals - I began to shop around for a different air supply. I ultimately settled on a set of twins - and I will tell you I don't regret it. As RDietze states about, there is little comprimise - good spool up (not quite as fast as before, but close), amazing mid and high range cooling. My EGT's rarely go above 1050 with the PPE/Hot Juice/EZ stack on full board.
Obviously, this is only my opinion. I would recommend twins if they are in your budget.
- Jason