have not tried their products.. caliber user will do justice to comment on their products.. i think its better to look at the specs of the amp.. caliber's products are relatively affordable here, that's why there's a lot of interest.. 1st of all is whether the power ratings suit the drivers u r gonna use, eg. nominal rms per channel, peak etc..
eg. lightning audio is branded but their bolt range of products don't attract good reviews...
here's some basic guide extracted/ edited from an expect on what to look 4 in an amp..
1. Damping Factor
Damping factor describes an amplifiers ability to control a woofer cone. It's the ratio of rated load impedance to the internal impedance of an amplifier.
The higher the damping factor the more efficiently an amplifier can control unwanted movement of the speaker coil. High damping factor is crucial for subwoofers and the higher the damping factor the better. It is debatable if anything over 50 is audible. The damping factor will decrease as the speakers impedance decreases. This means an amp optimised at 4 ohms will provide tighter bass than when they're running at 2 ohms.
A lower damping factor will leave bass notes sounding soft and undefined, regardless of the amplifiers power output. You can see by this that a smaller 100 watt amplifier with a high damping factor can often sound better than one twice it's size with a low damping factor.
2. Slew Rate
Sometimes referred to as damping factor for tweeters, the slew rate describes the amplifiers ability to accurately control fast direction changes of a speaker cone or dome. Measured in volts per microsecond, a low slew rate softens the definition of a sound signal which blurs transients and causes the sound to appear muddy. A high slew rate means the amp responses faster which ultimately results in crystal clear highs.
3. Total harmonic distortion
THD is the measurement of the how much the amplifier can distort the sound signal through the introduction of added harmonics or overtones.
THD figures are usually given as percentages and a THD figure below 1% are generally inaudible to most people. However, distortion is a cumulative phenomenon so if your head unit, eq, crossover and amplifier are all rated at less than 1%THD each, together they could produce 5%THD which may well be noticeable to most of you.
4.Signal to noise ratio
Noise leaking into the sound signal is an ever present problem in car audio. The Signal to noise ratio is a measurement of noise level in the amplifier compared to the level of the signal. A higher S/N ratio signifies a greater difference which is better. Technically speaking, it's the ratio expressed in dB of signal power at a reference point in a circuit to the noise information that would exist if the signal were removed (the noise floor). The maximum signal to noise ratio of the amp can be seen as a measure of realistic fidelity. This ratio is how much absolute noise it produces compared to the highest signal voltage it can pass without distortion.
5. Stereo separation.
This refers to the amplifiers ability to maintain the separation between the right and left channels. This is essentially what allows an amplifier to reproduce an accurate sound stage.
Each individual instrument is after all, are recorded in it's own location in the sound stage and you should be able to hear this in the same way when it's played in your car.
Loading is another issue to consider. Watch the impedance of speakers when choosing them because while most amps are stable at low impedance levels, they're not overly efficient nor performing 100% when loaded down.
Many amps are 2 and 1 ohm stable but this is for intermittent spikes (as music is dynamic it causes the speakers resistance to continuously change during playback), not continous everyday running.
