When installing aftermarket mufflers...How important is back pressure?

I know that having to much back pressure is bad. Is not enough back pressure also bad? Should I consider this when shopping for new mufflers. There are so many aftermarket exaust products out there, I don't know which one is the right one for my car. Most of us buy them because they sound good without putting much thought on things like, too much back pressure or not enough.

 

It wasn't an item influencing my decision. I chose the FRPP axle back made by Borla. There is no noticeable performance difference.

 

Being such a high horsepower car, with a larger displacement your going to want less back pressure. Smaller displacement motors want more backpressure to a point, barring power adder cars. Won't make much of a difference in your case.

Roger