First was cans (borla), then added 200 cell cats and x51 headers. Great but wanted more volume. Cans off and muffler bypass on: too much volume. Cans back on. Just got a set of cat bypass from fabspeed and on in an hour ( thanks to Alex for getting to me quick). Fit and finish great, sound great. Love it. A bit more volume than 200 cell but livable compare to muffler bypass. No change in drone (was minimal before below 2500 rpm) but now it screams at WOT. Very pleased. No cel thanks to softonic tune. Once the dectane led's are on I will be done with modding (wife Skeptical about this statement lol!). Have had thoughts about plenum +\- intake (have BMC filter and fabspeed red hose now) but many have said there is not much restriction in stock setup anyways so will prob hold off. Will try to get a vid up soon.

 

Did you have the x pipe 200 cell cats or the regular straight ones? And the cat bypass, X or two piece straight?

 

Both are x-pipes by fabspeed.

 

Gator Skin:

Last week I had my local shop here in Taiwan fabricated a set of X-pipe cat bypass (much like the fabspeed design) mated to my PSE, I love the low end exhaust note but I don't like the high rpm "scream" it makes. Wonder if the high pitch scream is due to the exhaust gas merging on a flat 6. My AMG E63 V8 sounded incredible with high flow cats and X pipe without the high pitch sound on high RPMs.

Does yours make a high pitch exhaust sound maybe it's my PSE that is causing it?

Do you feel lost of low end torque at all?(which I do and hoping a Softronic tune will fix it).

Right now I am thinking of going to a set of straight through 200 Cell cats from AWE if I can confirm the high pitch sound is cause by the cat-less X.

 

Mine's more of a low pitch scream, probably due to the Borlas. All they added sound-wise from the cats was some volume. I did notice a bit of low end tq loss with the cats but it improved with the softronic flash. No change going from cats to catless with flash on board. I've heard that the more sensitive throttle response from softronic or a pedal chip (sprintbooster), get you into the higher rpms quicker where the increase hp/tq has been shifted to by the less restrictive exhaust mods.