The Firewire interface really only serves the purpose of getting the audio into the computer, and has little to do with controlling the kinds of things that make the audio "sound" good.
Assuming you are looking for a very "large" sound (like the sort of clean and precise recordings on albums or television, you probably want to research actual pre-amps as opposed to Firewire interdaces:
http://aphex.com/204.htm
Is a popular model for VO recording.
There are literally hundreds of similar products, whose goal is to capture sound clean and big without distortion.
Your mic will work for this, but needs to have the proper preamp on the front end (between mic and Firewire interface).
There are software programs that can do similar results, but you run a much higher risk of introducing digital distortion or audio artifacts if you send an uncontrolled voice signal directly to most Firewire interfaces.
For purposes of VO audio, especially, the "pre-amps" listed as part of the Firewire specs really mean nothing.
Run a search on mic pre amps for more.
The king of microphones are the large capsule Neumann condenser mics.
These are used on probably 70% of all major hit records in the last 50 years and range in price from a few hundred bucks to over 20k.
Good luck.
And don't skimp on the cables. They do make a difference.