I'd like to comment on the increasing range of plugins that emulate specific hardware. There are large differences between those that appear to emulate and those that are physically modelled. The painstaking mapping of voltage curves and behaviours from actual hardware units is by far the most accurate approach to embedding the actual tonal colour of a circuit topology. Any analogue device will colour your signal simply passing your signal through it. If the plugin you're considering does not do this prior to adjusting any parameters then I'd suggest it is an inferior design. My advice is to run a demo before purchase; always. With models such as those by Universal Audio there is an immediate alteration to the tonal characteristics - that's why they are considered some of the premier designs available. Listen. If your eyes are making the decisions I'd recommend optometry rather than audio engineering.