best cat back exhust system for deep sound
 

what is the best cat back exhaust system for my sierra denali in terms of sound deepness?

gibson?
borla?
corsa?

Flowmaster .

For sound and performance, Magnaflow with 4 inch tips. The tips will give you the deep tone you want. Having turn downs is ok but you get too much cab drone. A single in and dual out Magnaflow muffler with 4 inch tips on both pipes will give you pretty close to a big block sound, IMO.

what do you think of the gibson?

Gibson is good. Gibson gives more of a raspy sound, like the cherry bombs. Flowmaster's give more a hollow chambered sound. Magnaflow sounds real similar to flowmaster but you can tell the difference in performance. More torque with Magnaflow. Go here for some sound clips...http://www.magnaflow.com/04sound/04trucks.asp

Ive heard a few gibson's and they sound good for the money

Gibson has a lot of nice reviews when it comes to the list of branded exhaust systems and it's a great product too. When it comes to sound deepness the Gibson has some nice noise compered to some other exhaust systems.