Well I personally have never ran Borla on my truck, but I have had friends that did and they werent happy. Actually I have heard guys on the board say its not loud enough. And going off whatyou said before, that magnaflow wont be loud enough, I assume Borla will be much quiter. I think Borla is a great quality system, just not woth the $$ to me for the sound.
Look up youtube clips. Although its not the best reference, you can clearly tell its not a "loud" exhaust system. It is known to be very mellow sounding. For example...
http://www.youtube.com/watch?v=b3qcVHI2A3Q
I would be running Corsa if I could afford it...but I didnt have that money when I did exhaust. I know if you get a small case magnaflow you can save a lot of $$ over borla and get it custom ran out the back how you want.
As you mentioned before you loved the sound of Flowmaster. Borla wont even be close. I say do a llittle research online before you spend all that money and end up upset like the wheels.
Lastly, not trying to come off mean or make you feel like you wont be happy, I just think from what you originally said you wanted, Borla wont satisfy you. It took me forever to pick my exhaust out.