Preamp and Amp how much influence each contributes?

assuming your front is pure digital streaming or local hard drive. 

I've heard preamps that influenced the sound character as much as amplifiers have.

But the reality is amplifiers are a more difficult product to consider because of the need to consider what sort of load it is driving (i.e. the speakers). And thus the larger number of questions and opinions about amplifiers.

I don't think an integrated amplifier is automatically equal to lower sound quality when compared to separates.