You could probably squeak a few more hp out of it with some bigger injectors and a full tune. But hey, for the money you have spent on it, if it runs reliably and you're happy with it, I wouldn't mess with it. I was cranking almost 500 to the wheels with 30lb injectors on the dry kit, which essentially does the same thing as an FMU. The fuel numbers were pretty spot on, and it ran nice and smooth.
Kurt