I'm with Kal - why big differences? The extra power you get in BTL mode may be overkill for your small monitors - you may be already pushing the limits of what you can eek out from them. Speakers compress when driven really hard and will start to sound dull - up to a point adding power is helpful especially in the bass response (but if you use a powered sub then you may not notice this) and then it quickly becomes diminishing returns on small monitors.