wow, you dont even know what you just opened up. Asking what the best sounding mufflers are for this car is like asking asking what is everyones favorite beer. Many answers, but personal experience is the best way, I personally dont like the magnaflows because they are a bit raspy, but others love them. Here is what I have learned from my experience, but these are only my personal opinion.
Magnaflow: Too raspy with a tingle noise.
Flowmaster: Deep, throaty, and pretty silent unless on the throttle.
SLP Loudmouth: Nice low rumble on idle, nice deep tone all throughout the rpms, but some say too loud.
Borla: Nice sound like the loudmouth system, but way too over prices IMHO.
Anyone else have input???
If you would like to hear my flowmasters and arent too far from me let me know, but i would try to hear them all first.
As far as performance goes, I am not sure what each system adds, but my flows seem to have dropped my torque quite substancially, but seem a bit better on top end high rpm range.