From the Absolute Sound...
The STA200 is a Class A/B amp with 80 watts of output into 8 ohms, 34.4dB gain.
With some preamplifiers, the STA200’s high gain could mean that the preamplifier could be operating in a less than optimal gain range.
http://www.theabsolutesound.com/articles/optoma-nuforce-sta200-power-amplifier/
SVS Speakers...
freq. response: 45-32,000 Hz (±3dB)
recommended amplifier power: 20-150 watts
sensitivity: 87 dBnominal impedance: 8 ohms
bass-reflex cabinet with rear-firing port
Your speakers are 8 ohm so they should be a good match in terms of sensitivity and power with your amp.
As you stated, the NuForce has a high gain and would match well with a preamp of approximately 12 to 15dB.
The 2 or 3db quoted to you may really be 12 or 13dB.
Since your source is TT, the gain of the cartridge and phonostage also must be considered.
Do you know what cart you will be using?