What have you guys who upgrade from a 100-140 watt amp to a 200+ amp noticed. Please reply if you upgraded in the same brand like a Parasound 85 to a 145 or higher. Are the benefits large or subtle? Just giv eme you opinion, we can fight on semantics another day. Thanks. How do you think a low-powered amp plus pre-pro compares to current mass-produced mid-level receivers- HK525, Denon 3803-4802, Onkyo 800-900 types. Thanks.