Ka Drifter

I was reading on one of the sites how to do a leak down test on the fuel system. But let me know if this is about the same or if I have to do it another way. I have a fuel pressure gauge right after the fuel filter when the car is running it is at like 40psi. But when i turn the car off it goes down to like 20psi(yes i know it will go down with out the car running)But how much is to much? The reason I ask is that when my car sits over night it is real hard to start in the morning and i can smell gas. So is one of the injectors bad? And is this a seal problem or a internal problem? If it is internal problem could i have these injectors rebulit by RC Eng. or would I have to buy new ones? What can you upgrade the injectors to with out having to have the computer remapped? Or could i buy after market one and control it with a APEXi AFC?
Thanks