Magnaflow Duals Install Update

Installed Magnaflow "GT-Cat Back" (Not the Magnapacks) with "X" pipe..see attached pix. Looks great, sound on start up & idle a deep (not too loud) rumble and WOT is very strong...not at all ricey. HOWEVER---Before the install my 2007 5 speed manual with no mods and only 5000 miles ran better.
Yeah...better!! In third gear, I could tap the gas pedal and the front end would smartly jump up ready for action. Now after the duals are in...that perky response is gone...gone...gone. Still pulls OK thru the gears, far as I can tell but I've definately lost some low end torque. Did I mess up getting the "X" pipe? SCT X-Cal sure, but cannot risk voiding the warranty-much too new a car! Need SOUND advice (No pun intended) Thanks in advance guys!!

Magnaflow Woes

Hey Guys-Thanks for your opinions but in my mind getting an SCT Xcal tune would in effect be putting a bandaid over the root problem instead of actually trying to address what's really wrong i.e. I've opened up the exhaust too much-enough to adversely affect my low end performance. I admit to you that I'm not sure what to do, that's why I'm seeking your advice. I guess I'd like to have the duals but not have to sacrifice low end torque-or am I asking too much form the 4.0? Somebody out there must have had similar issues-Would really appreciate more input. P.S. Yeah here's a closer look. Thanks