The Borla over the flowmaster? The borla on the NA sounds real high-pitched and "civic-like" for me...
I put a 50 series Flowmaster NON DELTAFLOW on my NA, I love it. It sounds real throaty and deep, almost like a small block V8, which it has been mistaken for by a few people. A set of glasspack exhaust tips took care of the slight rattle they make at certain RPMs. It is not too loud in the car and it definately does not have the drone of the borla. The 40 series is deeper and throatier, but it definately borders on obnoxious

The 50 series is the way to go!
I've had it for a year now and love it. It takes about 500-1000 miles for it to fully break in, so it might be a little rattly and such when you first get it, but all new exhaust are like that!
It'll be cheaper than any other exhaust 'system' you could buy anyway. my 2.5" piping into a 50 series flowmaster and out both sides of my car cost $280 total out the door...