so you're using the cubaseLE that came with your firepod instead?
didn't you just say that you're not experiencing the latency issues in reaper? not to be condescending, but if you're talking business, and can't afford things to go wrong, why don't you use what works? the click is totally customizable, or you could just use an external click vsti (which is what protools users do, in case you think that's cheating) and i think most users would agree that reaper is significantly more powerful and functional as a professional DAW than cubaseLE. now if you were talking cubase5, or nuendo, that'd be a different story, but in this case, comparitively cubaseLE is pretty weak, and little more than a good start for most firepod users.
back to the topic, latency varies significantly from plugin to plugin and the power of your system. there's zero latency plugs, and there's plugs that add a few milliseconds. it's even variable for some, such as drumagog, which has a less functional zero latency mode, and an advanced mode for post production that can add up to 80 ms. cubase "compensates" automatically, like most DAWs, so that everything plays back synced up. but this can be problematic if you're still trying to track and already have a ton of things going on. adjusting the hardware buffer in your cubase audio hardware settings and reducing the firepods latency controls (you should be able to access the firepod control panel by right clicking the little presonus icon in the system tray) can help reduce noticable latency times.