While we are waiting for your samples I'd like to say this.
UTAU is very picky about the mic you use, the environment, etc.
A mic that sounds good to your ears may not actually be good enough for Utau.
Things like electric interference (static in your recordings), environmental noise (running fan/AC, TV, People thumping around), and room feedback (echo, reverb, etc), or just the frequency response/quality of the mic itself.
When recording I recommend keeping your environment as silent as possible and you should be as loud as possible
without yelling. It should still feel very natural and comfortable.
It would be great to know what kind of mic you have so we can know how it connects to your computer.
Some mics use 3.5mm plugs to connect to your PC, these are common and rely on the quality of your computer's built in sound card. Generally computers have really poor built in recording and even separate soundcards still tend to be really bad at it unless it was actually designed with that ise in mind.
Mics and interfaces that use a USB connection are popular because of the built in electronics. These deviced aren't handicapped by your computer's built in audio so you often get a really nice result when the mic is decent.
FRQ files will not make your voicebank sound metallic, all FRQ files are is a measurement of the pitch of the sample. The most that can happen is that it jumps and your UTAU voicebank has some popping in certain sounds. Which can be fixed by hand.
While we still don't know what mic you have, if you are in a bind and need one then you can look at USB Headset microphones.
They aren't super high quality but they are cheap and do the job well enough for practice. I recommend Logitech brand ones as those are generally decent and you can buy them at your local Walmart or electronics store for $30.
Sorry about the wall of text! Kinda got carried away.