PLEASE TELL ME...WHAT EXHAUST MOD HAS GOTTEN THE BEST RESULTS (SOUND AND PERFORMANCE)? DYNOMAX/FLOWMASTER? SINGLE/DUAL? I GOT A QUOTE FOR DUAL FLOWMASTER 70 MUFFS WITH RESONATOR ELIMINATION AND TIPS FOR AROUND $300!? IS THIS A GOOD DEAL AND WILL IT BENEFIT ME IN PERFORMANCE!?